1853.] COLES SKIN OF THE ICHTHYOSAURUS. 79 



lar, so that two pits, a few yards apart, may present two totally 

 diiferent sections ; as though the beds had been deposited by means 

 of strong conflicting eddies and currents. They consist sometimes 

 of stiff red and yellow clays, like those in the gullies ; but there also 

 frequently occur beds of a very hard reddish concrete, composed of 

 quartz and slate pebbles. At Ballarat large boulders of quartz, 2 or 

 3 feet in diameter, were found imbedded in the auriferous clays, and, 

 more rarely, detached masses of a conglomerate of fragments of lava, 

 trap, and quartz, imbedding rounded pieces of gold. At these work- 

 ings the rich " pockets " of gold were commonly associated with a 

 bluish clay, running in irregular veins and patches. So rich was this 

 clay, that 9 lbs. weight of gold have been taken from a single tin- 

 dishful of it, about 14 inches in diameter and 5 or 6 inches deep. 



Enormous amounts of gold have been taken from some of these 

 rounded alluvial hills. The yield, however, is not so uniform as in 

 the gullies ; a rich spot and a barren may often lie close together. 

 In these deposits, as in those of the dry gullies, the gold is usually 

 imbedded in red or yellow clays, lying immediately on the funda- 

 mental slates, or on the "pipe-clay." When the gold-yielding clay 

 lies on the rock, small lumps or nuggets of gold will sometimes slip 

 down between the vertical slates. 



In conclusion, the methods of separating the gold from the gravels 

 and clays are the same as those used elsewhere in New South "Wales 

 and California, and vary of course according to the means at the 

 command of the miners*. 



February 23, 1853. 



James Bright, Esq., M.D., David Forbes, Esq., and Joachim 

 Otte, Esq., were elected Fellows. 



The following communications were read : — 



1. On the Sktn of the Ichthyosaurus. By Henry Coleis, 

 Esq., F.G.S. 



[Plate V.] 



Some years ago, I had the opportunity of collecting a number of 

 Saurian remains from the Lias quarries on the line of road between 

 Tewkesbury and Upton-upon-Severn ; but, not having leisure at that 

 time to arrange them, I packed them up without cleaning, hoping I 

 might be able hereafter to examine them more thoroughly and care- 

 fully. About eighteen months since, when scraping the clay from a 

 vertebra of one of these Ichthyosauri, I noticed a number of minute 

 black points. On looking at them through a microscope, I was much 

 struck by their resemblance in form to teeth ; and, on placing a 

 fragment of the layer of carbonaceous-looking matter with which the 

 vertebra was partially invested, under the microscope, it appeared 



* [Besides the Ballarat and Mount Alexander gold-fields, " diggings " have been 

 opened at Mount Blackwood and on the Moorabool River, near Ballarat ; on the 

 Plenty and the Yarra Yarra Rivers, N.E. of Melbourne ; on the Mitta Mitta River 

 and Lake Omeo, in the N.E. part of the Colony ; as well as at several points along 

 the eastern portion of the Boundary-line between Victoria and New South Wales. 

 —Ed.] 



vol. IX. — part I. G 



