230 



SCIENCE. 



[N. S. Vol. IV. No. 86. 



gheny from the north were covered by the 

 Kansan advance and filled with its debris, 

 They were afterwards more or less excavated 

 and filled with later modified Wisconsin ma- 

 terial ; but immediately and at a moderate in- 

 terval in the past, as is shown by two facts: the 

 state of the crystallines in the Kansan drift, 

 and the condition of the river gorges. 



The writer, several years ago {Am. Jour. Sci.), 

 made the statement that the majority of glacial 

 students seemed to have failed to consider the 

 state of the surface immediately before the first 

 glacial advance. He, thereupon, stated that all 

 portions of surface outcrops too hard to be 

 ground into flour would form a rusty gravel, 

 with the rustiness due to previous weathering, 

 and not to lapse of time since deposition. This 

 is fully proved in the Kansan drift in western 

 Pennsylvania, where red granite cobbles have 

 been found on top of the hills east of the Alle- 

 gheny river, and from four to five hundred feet 

 above it, and these have been glaciated on one or 

 two sides, where the smoothed surface acquires 

 the aspect of ' rusty gravel,' while on other sides 

 the old surface weathering remains undisturbed 

 to such an extent that the rock has lost en- 

 tirely its black bisilicates, is completely kaolin- 

 ized and is pulverulent. One side is scraped 

 down to the hard and rusty interior, and the 

 other remains as it lay on the surface when 

 picked up by the ice. In the same way local 

 Pocono and Carbonic sandstones will show a 

 hard glaciated surface and a pulverulent angu- 

 lar surface in the same fragment and in hun- 

 dreds of instances. These lie in red clay on 

 local white sandstone. With these ancient relics 

 are sparingly mixed river-rolled sandstones 

 and shales as highly polished and as hard as 

 any in the Wisconsin deposits. These are found 

 under conditions which exclude their being 

 residual from local weathered conglomerates, 

 and, as in eastern Pennsylvania, they bear wit- 

 ness to the close association of Kansan and 

 Wisconsin formations. 



The best proof, however, lies in the state of 

 the river bottoms. My assistant, Mr. Joseph 

 Barren, has discovered and studied the aban- 

 doned channel, not hitherto noted, of Oil Creek 

 below Petroleum Centre, and will discuss it 

 fally later. I wish to call attention to the im- 



portance of his discovery that both the old and 

 the present channels are of equal depth ; both 

 are filled with Kansan and modified Wisconsin 

 drift, and the creek has not cut down to its 

 preglacial or Kansan level since the glacial 

 epoch. 



As the finding of Kansan drift over the region 

 shows that high and low level gravels could 

 accumulate from the same source, so the dis- 

 covery of this filled valley, under exactly simi- 

 lar conditions which obtain in the Lehigh region, 

 shows that Kansan and Wisconsin advances, as 

 far as the State of Pennsylvania is concerned, 

 were closely allied and not very remote. 



Edward H. Williams, jr. 



Lehigh University, August 3, 1896. 



A LARGE LOBSTER. 



The subject of the size attained by the lob- 

 ster has been recently treated by Herrick in his 

 work on the Habits and Development of the 

 American Lobster. 



Various exaggerated reports of lobsters weigh- 

 ing 30 to 40 pounds have appeared as news- 

 paper items, but the authenticity of such state- 

 ments is questionable. 



Herrick describes a specimen captured at 

 Boothbay, Me., in 1891, and now in the museum 

 of Adelbert College, which is probably the larg- 

 est on record which has received accurate meas- 

 urements. 



On April 10, 1896, there was captured near. 

 Block Island a fine specimen which closely ap- 

 proaches in size the one described by Herrick, 

 This was entangled in a trawl line in deep- 

 water, and so captured. It passed through the : 

 hands of Mr. E. 0. Smith, a lobster dealer of 

 Newport, E. I. , and is now in the possession of 

 Mr. F. W.Wamsley, of Woods Holl. It is des- 

 tined for the museum of the Academy of Natural 

 Science at Philadelphia. 



The specimen is a male, perfect in every re- 

 spect, and weighed alive slightly over 22 pounds. 

 I have carefully measured it and find that the 

 total length from tip of rostrum to end of telson 

 is 21 inches. The greatest breadth of carapace 

 is 5 J inches, while the girth just behind the cer- 

 vical groove, from edge of branchiostegite of one 

 side to same position on other side, is 13| inches. 

 The crushing chela is on the left side. The 



