1879.] involving repeated differentiations. 271 



I met with the theorem (1) in connecting certain solutions of 

 ihe differential equation 



d\ 2 _ * (*' + 1) 

 dx"" x" 



which is a known transformation of Eiccati's equation. 



(6) Mr William Crookes, F.RS., On molecular physics in 

 high vacua. 



Mr 0, Fisher, M.A., F.G.S., Notes on a mammaliferous deposit 

 at Barrington, near Cambridge. 



[Eead February 10, 1879.] 



Excavations in the neighbourhood of Barrington, for the purpose 

 of obtaining the phosphatic nodules of the upper greensand, have 

 lately revealed the fact that mammalian remains of the earlier 

 pleistocene fauna are remarkably abundant in the superficial gra- 

 velly sUt which there in places overlies the cretaceous deposits. The 

 village of Barrington stands partly upon these quaternary deposits; 

 and a small "coprolite" pit, which was opened to the east of, and 

 nearly opposite to, the blacksmith's shop upon the Green, proved 

 very rich in these remains. The larger part of the collection now 

 in the Woodwai'dian Museum was however collected about half a 

 mile further down the valley, upon land belonging to Trinity 

 College, at a pit worked by Messrs Smith and Badcock. Here 

 Mr Keeping, the curator of the Museum, spent about a fortnight 

 in the autumn of 1878 in searching the locality: and the result 

 has been a collection, consisting of about 360 Museum specimens. 

 The spot may be recognised upon the ordnance map as being near 

 where the final n in the word "Barrington" is printed. The tract 

 of ground, in which the pit was opened, is about twenty feet above 

 the alluvial flat where the river Rhee now runs. There is a small 

 streamlet, running in a contrary direction to the Rhee, between the 

 locality and Barrington Hill; so that the silty' gravel is upon the 

 highest part of the low tract between the hill and the river. The 

 hill may be a hundred and fifty feet or thereabouts higher than it ; 

 and lies to the north of it. 



The levels proceeding southward from the pit may be taken to 

 be as follow : 



Vol. III. Pt. vi. 20 



