o 



1^ 



Correspondence — G. Oreemvood. I'Jl 



[Lino of unconformity.] 

 ' C. White or grey sand, nioro or less colioront, and with occasional 

 ferruginous stains, sometimes ((uiirried for building-stone. A 



plant-bed is usually found in this sand 12 



' D. A series of very variable beds, composed sometimes of ferruginous 

 sandstone in thin layers, which overlie calcareous beds containing 

 shelly zones, false bedding being frequent. Sometimes the whole 

 section consists of calcareous rock with false bedding ; sometimes 

 it presents a series of beds of compact ferruginous sandstone, 

 with no fossils. In one instance the entire section consists of white 



sand and sandstone, with no fossils 30 



Coarse Oolitic or subcrystallinc Limestone, with fossils, overlying a 



calcareo-arenaceous slate, like Coileyweston Slate 4 



u ( E. Bods chiefly consisting of Ironstone, containing Rhynchonella 

 ^ \ variabilis and B, cynocephala, and Ammonites bijrons at the 

 ^ ( base 35 



:hS 



o 



A 

 o 



a 



Cm 

 ^ L 



This general section, the author stated, might be accepted as a 

 typical section of a considerable portion of the county of North- 

 ampton. 



In his concluding remarks the author referred to the great lime- 

 stone which marked the country about Stamford, and traversing 

 Rutland, attained its greatest thickness in Lincolnshire. This 

 limestone was proved by its palaeontological contents to be Inferior 

 Oolite ; and its place, with reference to the beds described in the 

 paper, was shown to be in the interval (marking the line of uncon- 

 formity) between B and C of the general section. It thus tended 

 to confirm the statement of the author that the line of division 

 between the Great and the Inferior Oolite in the neighbourhood of 

 Northampton occurred at that point. 



The paper was illustrated by the exhibition of a large collection 

 of fossils from the several areas, including some new species, promi- 

 nent among which was a new Starfish, named, in compliment to the 

 author, " Stellaster Sharpii," by Dr. Wright, F.R.S.E., F.G.S., and 

 described by him in a Note appended to this paper. 



Discussion.— Mr. Smyth commented on the great value of careful observations by 

 local geologists, such as those brought before the Society by Mr. Sharp. 



Mr. Etheridge pointed out how a few years ago it was supposed that hardly a 

 fossil was to be found in these Northampton beds, and that they all belonged to the 

 Great Oolite, and not to the Inferior, an error in which the Geological Survey had 

 shared. The district was, however, now being resurveyed under the new light 

 thrown on the character of the rocks by the extensive quarrying which had taken 

 place during the last few yenrs, and which hiid afforded the opportunities so judiciously 

 utilized by the author of the paper, who had plneed the order of succession and the 

 character of the Northampton Beds beyond dispute. 



Prof. Morris had found a difficulty in reconciling the phenomena of the eastern and 

 western Oolitic areas, but considered that the key of the arrangement was to be 

 sought in the district between Northampton and Stamford. 



Mr. Sharp briefly replied. 



ooiEaiaESX'on^^riDEnsroiE- 



EESTOEATION OF DIMOEPHODON. 

 Sir, — Haven't they prolonged the wrong claws, or toes, or fingers, 

 in Fig. 2, Plate IV. ? George Greenwood, Colonel. 



Brookwood Fark, Alresford, March 1, 1870. 



