382 Geological Society : — 



position and relations of the " uncus " and "pecten " (" crochet " and 

 " anterior combing-plate," and the consequent absence of the cha- 

 racteristic u tichorhine pit" or fossette. The less strongly marked 

 characters by which the teeth could be distinguished from those of 

 R. JiemitcecJius, Pale, and R. etruscus, Falc, were also pointed out. 



The metacarpal bone selected for the illustration of the diagnosis 

 is 9| inches long, and remarkable for the compression of the shaft 

 and its comparative slenderness, as contrasted with the same bone 

 in R. ticJiorhinus, specimens of which were exhibited on the table, 

 and which, in no case within the author's knowledge, ever exceeds 

 7 J or 8 inches in length, and is proportionally much thicker than 

 in R. leptorliinus or any other extinct species. The size and form 

 of the bone also showed that the species could not be either R. hemi- 

 tcechus or R. etruscus ; for although the means of direct comparison 

 with the third metacarpal of those species did not, to the author's 

 knowledge, exist in London, its probable general dimensions and 

 proportions could be deduced from those of the corresponding meta- 

 tarsal, of which bone numerous specimens were available. It was 

 further shown that the Oreston metacarpal exactly corresponded 

 with those of R. leptorhinus, from Grays Thurrock, in the British 

 Museum. 



The determination of the species appears to be of considerable 

 interest, inasmuch as it affords an additional instance of the occur- 

 rence in England of the great southern Ehinoceros. This is also 

 the only example of the discovery of that species, except in river or 

 other deposits, either in this country or on the Continent. 



2. " On two Gneissoid series in Nova Scotia and New Bruns- 

 wick, supposed to be the equivalents of the Huronian (Cambrian) 

 and Laurentian." By H. Youle Hind, Esq., M.A. 



This paper described the relations of two gneissoid series in Nova 

 Scotia and New Brunswick, which have hitherto been regarded as 

 intrusive granites and syenites, and have been thus represented on 

 the published geological maps of those provinces. The author con- 

 sidered that these gneisses were in the main of Laurentian age, the 

 Huronian or Cambrian rocks occurring only in patches over a- vast 

 area of Laurentian porphyroid gneiss. 



The old gneiss was stated to be brought to the surface by three 

 great undulations between the Atlantic coast of Nova Scotia and 

 the Laurentian axis of America north of the St. Lawrence. These 

 axes were rudely parallel to one another ; and in the troughs which 

 lay between them the Silurian, Devonian, and Carboniferous series 

 occurred in regular sequence, the New Brunswick Coal-field occu- 

 pying the central trough. On the line of section, in the troughs 

 to the north-west and south-east, the Lower Carboniferous was 

 stated to be the highest rock series which has escaped denudation. 



The gold-bearing rocks of Nova Scotia are of Lower- Silurian age, 

 and rest either on Huronian strata or, where these had been re- 

 moved by denudation, on the old Laurentian gneiss. The gold is 



