6 THE CANADIAN NATURALIST. [March 



hooked eagle-like claws which must have been ten inches in 

 length. The collections of the Academy are of immense value, 

 and its Scientific Library is very complete, but it greatly lacks 

 room and light. Eflforts are now being made to secure a better 

 building. Among other things it possesses an extremely valuable 

 and very complete collection of American skulls, which have 

 afforded materials to Morton, Wilson and Meigs for elaborate 

 investigations on the cranial characters of races, and which are 

 scarcely yet exhausted as sources of information on this very 

 important subject. 



Two works are now in progress in Philadelphia, which will be 

 of great value to students of American Palaeontology. One is a 

 monograph on American fossil mammals, by Leidy ; the other a 

 monograph on American fossil reptiles, by Cope. One of these 

 is to be published in the Transactions of the Philosophical Society ; 

 the other in those of the Academy, — both active Societies and 

 fellow-workers in the cause of science. 



Baltimore, though a queenly city, does not stand so high as 

 Philadelphia in scientific work. It has, however, its Academy 

 with a band of zealous naturalists, of whom Tyson, Morris and 

 Dalrymple were old friends, and others I was glad to meet for the 

 first time. The vicinity of the city presents a strange association 

 of old and new rocks, characteristic of that line of junction of the 

 more recent formations of the coast with old metamorphic rocks, 

 on which so many American cities have been placed. In the 

 quarries near the town are gneiss, hornblende schist and granite, 

 which have much of the aspect of Lauren tian rocks, and accord- 

 ing to Mr. Tyson's sections may be of that age. To a northern 

 visitor they are remarkable for the depth to which they have been 

 decomposed by the weather. Similar rocks in Canada usually 

 present a hard polished surface, as if incapable of decomposition ; 

 here there are many feet of " rotten rock " at the surface. The 

 causes may be : 1st, the more rapid waste of felspathic rocks 

 under a warmer climate and a larger rain-fall ; 2nd, the want of a 

 tenacious clay covering ; 3rd, the absence of the great Northern 

 drift and its ice-striation and polishing. There does not seem to 

 be any evident difference in the composition of the rocks to 

 account for it. Another point of interest is the extremely red 

 colour of the sand formed from the decomposition of the horn- 

 blendic portions of the rock. The oxide of iron resembles 

 anhydrous peroxide in its colour ; and the sand formed from it 



