finer grained types; from highly gneissoid to very slightly or moderately gneissoid facies; and from notably granulated to only moderately granulated varieties. The effect is to give bands or layers of varying composition, color, granularity, foliation and granulation, yet all clearly belonging to a single rock body. Such bands or layers usually vary in width from an inch to a hundred feet or more, and in length from a few feet or rods to a quarter of a mile. Banded structures of this sort are common throughout the Adirondack region, but it should be made clear that they are by no means universal. Large bodies of syenite or granite are often remarkably uniform and free from any notable variations or banding. Bands of amphibolite which, in many places, cause the syenite or granite (more especially the latter) to exhibit a very pronounced banded structure are not considered in this paper. These present some puzzling features and data regarding their significance are now being gathered by the writer. Also, distinct inclusions of various types of undoubted Grenville gneisses which, in the form of lenses or layers, in many places produce a banded structure are not discussed except in so far as they throw light upon some banding of the syenitegranite which has resulted from magmatic assimilation of such inclusions.

Of the many hundreds of observed examples of banded structures considered to be essentially the result of magmatic differentiation, a few will be described in order to give a proper conception of the more common and characteristic variations.

On the mountain spurs, respectively one mile northeast and two miles east of Whitehouse (Lake Pleasant quadrangle), there are shown many facies of the syenite-granite series ranging from greenish-gray hornblende syenite and granite syenite to gray and pink granite and coarse, almost prophyritic, granite. Such rocks play back and forth upon each other by sharp transitions repeatedly for a distance of one half of a mile on each mountain spur where the almost barren ledges are conspicuously banded in layers usually from a few feet to a few rods wide and parallel to the folia

tion. These bands show many diffenences in foliation, granulation and granularity. Variations of this sort are perhaps the most abundant throughout the Adirondacks.

By the road one and one half miles southwest of Long Lake village (Blue Mountain quadrangle) a freshly blasted ledge finely exhibits bands of greenish-gray syenite, granitic syenite, and gray granite. One band of light gray hornblende granite two and one half feet wide passes by insensible gradations into greenish-gray pyroxene syenite on either side. The bands are parallel to the foliation which varies considerably.

A hand specimen taken from a ledge by the lake shore near Adirondack village (Schroon Lake quadrangle) is distinctly foliated and granulated with a pink band especially rich in feldspar adjacent to a band very rich in quartz plus some garnets, these two bands having on either side gray granite consisting of quartz, feldspar, hornblende and some biotite. These very narrow bands, not sharply separated from each other, are parallel to the foliation. In the same quadrangle, one half of a mile north of Moxham pond, granite in a road metal quarry shows notable variations in coarseness of grain often within a foot or two.

The red hornblende granite of the northern portion of the Port Leyden quadrangle often contains bands of gray quartz syenite in subordinate amount parallel to the foliation. Good exposures are by the lower road crossing on Otter creek.

Professor Cushing, describing the granitic syenite of the Long Lake quadrangle, says:

Much of the rock is alternately green and red, quite quartzose, and a rock distinctly intermediate between syenite and granite, often passing into granite. Much of it is uniformly red, and the rocks range from syenite to granite in composition.1

Professor Kemp, in his description of the syenite of the Elizabethtown-Port Henry quadrangles, says:

The most acidic variety will quite sharply replace it (syenite); and in the same way a very basic variety may come in and constitute the section for 50 or 100 feet or more. Yet while the

1 N. Y. State Mus. Bul. 115, p. 478.

transition is sharp there is no evidence of separate intrusive masses.2

The interbanding of syenite and granite above cited as occurring in the Long Lake and Elizabethtown quadrangles are by Cushing and Kemp, respectively, interpreted as being most likely due to some process of magmatic differentiation. Kemp says that one is not "justified in inferring more than a differentiation of an eruptive mass into layers or portions of contrasted composition." For most cases throughout the Adirondacks, especially the very common occurrence of banded variations like those illustrated in the above examples, the writer agrees with this interpretation since there appears to be no escape from the idea of some sort of differentiation of the magma into layers of varying composition. Transitions between layers range from sharp to very gradual, but in a typical case the whole body of rock is, as Cushing says, "manifestly bound together as a mass of eruptive material arising from a common magma." Whether or not the transitions are sharp, they are always marked by interlocking crystals.

But what were the physical conditions under which the differentiation occurred? Did the differentiation take place before, or after, or during the process of intrusion? The writer ventures to offer some suggestions by way of partial answers to these questions.

M. E. Wilson has discussed the banded gneisses of the Laurentian Highlands of Canada3 which are essentially very similar to those of the Adirondacks. In his summary Wilson says: 66 As regards the origin of the folded, banded and foliated structure of the gneisses, it is concluded that these are all genetically related in the Laurentian mountain-building deformation which acted upon the magmatic axil mass during its consolidation" and "that the principal factor in bringing about the heterogeneity of the Laurentian complex was differentiation aided by (orogenic) deformation during its consolidation."

Now, in the main portion of the Adirondack region the banded syenite-granite series shows 2 N. Y. State Mus. Bull. 138, p. 48. 3 Am. Jour. Sci., Vol. 36, pp. 109-122.

little, if any, folding due to orogenic pressure, and the foliation is essentially a magmatic flow-structure produced under moderate pressure, that is a pressure little or no greater than that which resulted from the shouldering action of the syenite-granite magma during its intrusion. Reasons for these conclusions are given at some length by the writer in a recent paper. Such being the case, orogenic pressure was not a principal factor in the profeature of the whole central belt of Laurentian duction of the banded structures of the Adirondack syenite-granite series. Wilson states that the banding is a very persistent Highland gneisses, but in the Adirondacks the more localized developments of pronounced banded structures strongly oppose the idea that they were produced under general regional or orogenic pressure. The writer believes, therefore, that orogenic pressure has not been a necessary condition for the production of banded gneisses such as those described in this paper.

It may well be conceived, however, that, in those portions of the rising magma where the shouldering pressure was greater, the differentiation into layers of contrasting composition, color, texture and foliation proceeded more readily, while in other (often large) portions of the magma, where the shouldering pressure was relatively slight, the conditions for differentiation into contrasting bands were not so favorable. The influence of pressure in the production of the banding is thus recognized. It is further believed that the syenite-granite magma rose very slowly and irregularly, and that there was differential magmatic flowage, especially in those portions where the contrasting bands were developing. Many of the bands are not considered to have consolidated simultaneously since alternating bands showing sharp differences in degree of magmatic flow-structure foliation prove that some of the layers were more fluid and continued to flow after adjacent layers were wholly or nearly consolidated. Accordingly, where the banded structures are well developed we may picture not only the slow intrusion of the 4 Jour. Geol., Vol. 24, pp. 587-619.

heterogeneous syenite-granite magma split up into layers, but also differential movements of the layers, at least during late stages of magma solidification. This conception does not, however, preclude the possibility of some differentiation after portions of the magma came to rest, or even before the intrusion began. In fact it is reasonable to suppose that the commonly occurring large-scale, irregular, gradual transitions from granite and granite porphyry to syenite and even diorite may have resulted from differentiation of the syenite-granite magma before, or during an early stage of, the intrusive process.

Another explanation, supported by field evidence, to account for at least some cases of banded structure should be mentioned. Thus at a number of localities gray or greenishgray basic syenite or even diorite bands occur in the syenite-granite series where dark Grenville gneiss or amphibolite inclusions are also common. Both igneous-looking bands and inclusions lie parallel to the foliation of the country rock. Sometimes the boundaries of the inclusions are very sharp, but in other cases they are not, and plainly more or less fusion of the inclusions has taken place. All stages from thoroughly fused and absorbed inclusions to others where little or no fusion has taken place may be seen. The thoroughly fused inclusions have a distinctly igneous appearance and their boundaries of course merge into the enclosing rock yielding a more or less well developed banded structure. Some typical cases of this kind of magmatic assimilation are described by the writer in a recent paper, and still others in various New York State Museum bulletins by the writer. Of the large number of cases which have come under the writer's observation, nearly all are of very minor extent, and usually such banding is definitely recognizable as having resulted from assimilation rather than pure differentiation. There is no positive evidence that large bodies of the syenite or granite have been appreciably changed in composition due to the incorporation or assimilation of Grenville rocks. Thus, while it seems certain

Geol. Soc. Amer. Bull., Vol. 25, pp. 254–260.

THE Commission met in New York at the Rockefeller Institute on Friday, May 17, 1918. There were present at the meeting: Passed Assistant Surgeon E. F. DuBois, U. S. N. R. F., of the Bureau of Medicine and Surgery, Navy Department; Dr. D. L. Edsall, professor of medicine and dean, Harvard Medical School; Mr. W. C. L. Eglin, chairman of committee on safety rules and accident prevention of the N. E. L. A.; Dr. Yandell Henderson, professor of physiology, Yale University and consulting physiologist of the Bureau of Mines; Dr. Wm. H. Howell, professor of physiology and assistant director of the school of hygiene and public health, Johns Hopkins University, member of the National Academy of Sciences; Dr. Reid Hunt, professor of pharmacology, Harvard Medical School, Secretary of Commission; Professor A. E. Kennelly, professor of electrical engineering at Harvard University and the Massachusetts Institute of Technology; Dr. Charles A. Lauffer, medical director of the Westinghouse Electric Co., Pittsburgh, Pa.; Dr. S. J. Meltzer, Rockefeller Institute, chairman of the commission, member of the National Academy of Sciences; Dr. Joseph Schereschewsky, Assistant Surgeon General, U. S. Public Health Service; Dr. G. N. Stewart, professor of experimental medicine, Western Reserve University, Cleveland; Professor Elihu Thomson, General Electric Co., West Lynn, Mass., member of the National Academy of Sciences; Lieutenant Colonel Edward B. Vedder, of the Army Medical

1 Held under the auspices of the Committee on Safety Rules and Accident Prevention of the National Electric Light Association. Edited by Professors Howell, Stewart and Thomson.

School; Major Frank G. Young, of the Ordnance Division of the War Department.

A telegram was received from Surgeon-General Gorgas that Dr. Charles H. Frazier, professor of surgery, University of Pennsylvania, is to represent his office. (In a subsequent communication Major Frazier accepted his appointment.) Conferees: Mr. P. H. Bartlett, Philadelphia Electric Company; Mr. Wills Maclachlan, Electrical Employers Association, Toronto, Canada; Mr. C. B. Scott, chairman of the sub-committee on accident prevention N. E. L. A.; Dr. F. E. Schubmehl, General Electric Co., West Lynn, Mass.

The object of the commission, the chairman stated, is to consider efficient methods of artificial respiration in emergency cases, as they are met with in peace as well as in war. For more than a century, England has had several life-saving societies, and many special commissions have been appointed to investigate the methods employed in resuscitation. In this country, about six years ago, a commission on resuscitation from electric shock was created for the first time, by the initiative of the National Electric Light Association. It is now generally recognized that efficient artificial respiration is, for such conditions, the best and practically the only means available for resuscitation. It requires but little consideration to realize that the need for an efficient means of artificial respiration is very wide-spread. The committee on safety rules and accident prevention of the N. E. L. A., of which Mr. Eglin is the chairman, agreed that the Third Resuscitation Commission should consider its problems from a general point of

view.

Mechanical Methods.-Dr. Meltzer demon2 For instance, in injuries to the head which stop respiration, injuries to the chest (especially double pneumothorax) in laparotomies during which the respiration ceases occasionally, in cases of shock which occur in peace and more so in the present war, in poliomyelitis with stoppage of respiration,

in post-diphtheretic paralysis, in poisoning by opiates, by volatile gases (ether, chloroform, etc.) by mine and fuel gases, poisoning by magnesium salts, in electric shock and in drowning.

strated in the laboratory for physiology and pharmacology, the efficiency of the method of pharyngeal insufflation in an etherized dog after complete removal of the anterior wall of the thorax, in which the lungs and heart were exposed to full view.

Dr. Rossiter, of the Carnegie Steel Company, demonstrated the latest device of the Pulmotor Company, which is not identical with the original pulmotor. He showed also the original pulmotor. He stated that he had resuscitated eight gas cases, in which the respiration had stopped. This was done by the original pulmotor, in which he had more confidence.

Dr. James M. Booher, medical director of the Life Saving Devices Co., demonstrated the lungmotor. He showed a number of bloodpressure tracings, taken from animals which had received artificial respiration by means of this apparatus. In reply to a question, Dr. Booher stated that in these experiments the lungmotor was connected with the animal by means of a tracheal cannula. (In human cases the lungmotor is applied by means of a face mask.) Dr. Booher left with the commission histories of a number of cases in which the lungmotor had been used. (The commision found no time to examine these written histories, but Dr. Booher mentioned verbally especially two cases. One of these

cases

was subsequently investigated by the chairman. The life of a poliomyelitis patient with complete paralysis of the respiration was maintained for thirty-six hours by means of the lungmotor. The reporting physician is of very good standing.)

In introducing Mr. Foregger, the chairman explained that the physician who was most competent to present the details of the apparatus of the Foregger Company is now in France. The apparatus consists in modifications of the insufflation apparatus of Meltzer. Among other changes, the apparatus carried an oxygen generator tank. In reply to a question, Mr. Foregger stated that the oxygen thus generated may last eight or ten minutes.

Manual Methods.-Mr. Eglin read a letter from Mr. M. W. Alexander, of the General Electrical Co., stating that he hoped the "commission would be very definite in recommending the prone-pressure method, as experience has proved its value."

Mr. C. B. Scott stated that the accident prevention committee of the N. E. L. A. had reached the point in its investigation where it felt that the prone-pressure method was best to recommend, bearing in mind that machines are not always available in emergencies. His own company had had nine successful cases of resuscitation by the prone method and three unsuccessful cases in which mechanical means were used.

Dr. Schubmehl stated that the prone-pressure method has been most successfully applied by their two hundred and twenty-five first-aid men.

Mr. Maclachlan stated that he had the duty of training possibly three thousand men in the prone method. Their system required the men to practise this method at least once a month. The men are instructed not to desist in less than three and a half hours, and that not till then should they listen to advice from a physician who might tell the operator that the patient was dead.

The secretary read the following parts of a letter from Professor Schäfer, of Edinburgh, to the chairman: "The prone method has been adopted exclusively for about twelve years by the Royal Life Saving Society, the only important organization in the British Empire whose object is the resuscitation of the apparently drowned. It has also been adopted for several years by the London and other Police Force, by the Board of Trade, by the Army and the Navy." "The most important thing is in cases of drowning to have something ready which any man can use; which will effect respiratory exchange-whether exactly as much as normal, matters very little."

RESOLUTIONS ADOPTED BY THE COMMISSION

In the discussion following the presentation of methods and evidence to the commission the following important facts were emphasized:

1. That in most accident cases no resuscitation apparatus is at hand for immediate use.

2. That reliance upon the use of special apparatus diminishes greatly the tendency to train persons in the manual methods and discourages the prompt and persevering use of such methods.

3. That police officers or physicians often interfere with the proper execution of manual methods, in that they direct that the patient be removed in an ambulance to some hospital, thus interrupting the continuance of artificial respiration.

4. That in many hospitals the members of the staff are not all acquainted with the methods of artificial respiration.

5. That in medical schools instruction is not properly provided for students in the manual methods of artificial respiration.

In view of these facts the following resolutions were adopted by the commission:

1. The prone-pressure or Schäfer method of resuscitation is preferable to any of the other manual methods.

2. Medical schools, hospitals, fire and police departments, the Army and Navy, first aid associations, and industrial establishments in general, should be urged to give instruction in the use of the prone-pressure method of resuscitation.

3. Individuals who, from accident or any other cause, are in need of artificial respiration, should be given manual treatment by the prone-pressure method immediately on the spot where they are found. It is all important that this aid be rendered at once. The delay incident to removal to a hospital or elsewhere may be fatal, and is justifiable only where there is no one at hand competent to give artificial respiration. If complications exist or arise, which require hospital treatment, artificial respiration should be maintained in transit, and after arrival at the hospital, until spontaneous respirations begin.

4. Persons receiving artificial respiration should, as much as possible, be kept warm and the artificial respiration should be maintained till spontaneous breathing has been permanently restored, or as long as signs of life are present. Even in cases where there is no sign of returning animation, artificial respiration should be kept up for an hour or more.

5. A brief return of spontaneous respiration is not a certain indication for terminating the treatment. Not infrequently the patient after a temporary recovery of respiration stops breathing again. The patient must be watched and if normal breath