304 



SCIENCE. 



[Vol. I., No. 11. 



Moreover, such Caraivora, ainong modern 

 species, will also devour the eggs and j'oung 

 of other Carni\'ora. Therefore the development 

 of equally strong parental instincts in the Car- 

 nivora themselves would have come about in 

 the same wa}-. It is evident, that, in this man- 

 ner, carnivorous animals of comparatively 

 small size may have been the means of exter- 

 minating the largest and most powerful beasts 

 and reptiles. 



Among nearly all of the existing mammals 

 and birds, the parental instinct is very remark- 

 ably developed in one or both sexes, usually 

 more so in the female. Many species, now 

 abundant, would soon become extinct if the 

 parents did not have remarkable sagacity in 

 pi'otecting their young against numerous ene- 

 mies. Many reptiles, fishes, insects, and still 

 lower forms, also show wonderful maternal 

 instincts. We cannot suppose that their an- 

 cient allies had these instincts in the same way, 

 nor to the same extent. In uianj- cases the 

 enemies to be pi'Otected against are of com- 

 paratively modern origin. New modes of 

 parental protection must, therefore, have been 

 developed or acquired as new enemies ap- 

 peared. The ways in which different species 

 protect their young are exceedinglj- varied, as 

 all naturalists know ; and manj- areas wonderful 

 as anj' habits known among the lower animals. 



The development of the powerful parental 

 instinct for the protection and care of the 

 young, in the earliest races of man, must have 

 been of vital importance in man's struggle for 

 existence in his primitive and comparatively 

 helpless condition. 



In fact, it is evident, that without this strong 

 impulse, and the intelligence necessary to 

 make it effective, neither man, nor any of the 

 species of mammals belonging to the higher 

 orders, could have existed, even for a short 

 period . 



Possibly the variations in the degree of de- 

 velopment of the parental care, in different 

 races of man, maj' be connected with the in- 

 crease of some races and the extinction or de- 

 cline of others. A. E. Verkill. 



LAKES AND VALLEYS IN NORTH- 

 EASTERN PENNSYLVANIA. 



H. D. EoGEBS, many years ago, pointed out the 

 connection between tlie lalves and the northern drift 

 in Pennsylvania. In a lecent report of the second 

 geological survey,^ Mr. White gives fuller informa- 

 tion on this interesting question, and shows that 



1 G. 6. Geology of Pike and Monroe Counties, by I. C. White ; 

 Special surveys of the Delaware and Lehigh Water-gaps, by H. M. 

 Chance. Harrisburg, 1882. 



the numerous ponds north of the Delaware Water- 

 gap (forty-two are enumerated) are generally held in 

 either drift-barrier or drift-enclosure basins, though 

 the depth of some of them seems partly dependent on 

 local erosion in soft shale. The largest is about two 

 square miles in area, and nearly all are less than forty 

 feet in depth. Their shape is generally round or . 

 oval ; but Long Lake, a narrow expansion of Tunk- 

 hannock Creek, three miles long, is an exception to 

 the rule; and, unlike the others, it stands just out- 

 side the so-called 'terminal moraine,' or margin of 

 the glaciated area. Glacial action is not regarded as 

 having effected great destructive changes in the pre- 

 existing topography, except in the way of ' pushing 

 or disrupting' rocks that were divided into blocks by 

 joints. The corniferous limestone, especially, has 

 suffered in this way; and its great bowlders, 'many 

 of them as large as a good-sized house,' are strewn 

 beyond its outcrop over a scored and polished surface 

 of cauda-galli grit. It would be interesting to learn 

 if such corniferous bowlders are limited to the gla- 

 ciated district, and do not occur farther south as a 

 result of simple weathering. All the larger valleys 

 of this region contain modified drift, on which the 

 streams flow without reaching the rocky bottom. In 

 the Delaware and Lehigh valleys, this drift extends 

 far beyond the limits of glacial action ; but in the 

 .Schuylkill valley, which heads outside of the glaciated 

 area, it is absent altogether (p. xvii. ). At and above 

 the Delaware Water-gap, the rocky channel is filled 

 with drift to a depth of jjrobably one hundred feet. 

 All the line of outcrop of the Marcellus shale, from 

 north of Eondout, N.Y., past Port Jervis, where 

 the Delaware joins and flows along it, even beyond 

 Stroudsburg, a distance of ninety miles, is an old, 

 wide, deep valley, buried in stratified drift; but on 

 passing out of the glaciated area, just south of Sciota, 

 some distance after the Delaware turns southward 

 through its gap, the same weak shale is occupied by 

 a valley less than a tenth of its former width. It is 

 therefore suggested that tliis buried valley was cut 

 by streams under the ice of glacial times. 



Narrow post-glacial channels of moderate length, 

 cut in the rock by streams turned from their open 

 pre-glacial valleys by di'ift-obstruction, are found at 

 several points. The drift-filling of the old Sawkill is 

 as much as three hundred feet deep; and the falls on 

 its new channel are a result and mark of its recent 

 adoption. Raymondskill Falls have the same cause. 

 The Wallenpaupack takes a short cut of two miles, 

 instead of following its old path of four miles, to the 

 Lackawaxen, and, on its new course, has eroded a 

 gorge seventy-five feet deep, ending in falls with 

 a total descent of two hundred and sixty feet in a 

 mile. Above the gorge, the stream meanders for ten 

 miles over a broad, marshy flat, falling only half a 

 foot to a mile, — the final stage of a lalce that must 

 have existed in the obstructed valley till the cutting 

 of the gorge drained it. It is very plausibly suggested 

 that all the cascades of this district " owe their origin 

 to a similar diversion of their streams by the drift- 

 darns thrown across their pre-glacial channels;" and 

 we believe that this cause of gorge, ravine and cas- 

 cade has a very general application in glaciated coun- 

 tries. 



The gi'eater part of the report following these 

 introductory pages is devoted to a detailed descrip- 

 tion of the geological formations of the district. 



Mr. Chance's surveys of the Delaware and Lehigh 

 Water-gaps, in the same report, include fine illustra- 

 tion of these notable cross-valleys in contour-line 

 maps and vertical sections; but their description is 

 chiefly geological. It may be noted, that the disloca- 



