236 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 3, 



chalk series in this county cannot be correlated with any particular 

 palseontological zone ; and in fact they descend to a much lower level 

 in the series in the north than they do in the south of the county. 

 Nor do these facts differ from what might be our previous anticipa- 

 tions, when we reflect that many of the chemical and mineralogical 

 characters of these beds must have been acquired, not at their ori- 

 ginal deposition, but during their subsequent " metamorphism." It 

 may, however, be safely asserted that distinct zones of life are to be 

 traced in the Lincolnshire chalk, and that, during the enormous 

 period occupied by its deposition, the fauna of the district underwent 

 numerous and important changes — changes which cannot, as in 

 some cases, be accounted for on the ground of variation in physical 

 conditions, as the remarkable uniformity of lithological characters in 

 the whole series indicates a corresponding permanence in the condi- 

 tions under which the beds were deposited. The work of identify- 

 ing and accurately defining these zones, however, can only be 

 attempted when extensive and carefully formed collections of the 

 chalk fossils shall have been formed, which in Lincolnshire has been 

 scarcely commenced. Under these circumstances, the remarks which 

 I can oifer upon these strata must necessarily be of a somewhat general 

 and superficial nature ; and I shall in a great measure confine my 

 attention on the present occasion to a description of the various beds 

 of red chalk which occur in the series and which have been mistaken 

 for the Hunstanton limestone, and to a determination of their true 

 position on palseontological and stratigraphical evidence. 



Attention has already been called in the first part of this paper 

 to the fact that in the southern part of this district we have, lying 

 directly upon the Hunstanton series, beds of arenaceous chalk full of 

 fragments of Inocerami, and of precisely similar character and 

 appearance with the beds at Hunstanton and other places in N'orfolk, 

 in which Mr. Rose has detected Turrilites tuberculatus, Sow., Pecten 

 Beaveri, Sow., and Ostrea carinata, Lam., and which he has conse- 

 quently described as Chalk-marl *. The same fossils occur in the 

 equivalent bed in Lincolnshire. 



Above this stratum we have, as in west jS'orfolk, a great thickness 

 of hard chalk, destitute of flints, the different beds of which present 

 considerable variation in chemical and physical characters. This 

 stone, as in ISTorfolk, has been extensively employed as a building- 

 material, and even for the purpose of sculpture. Thus a great part 

 of Louth Abbey, erected in the twelfth century, is constructed of 

 this material ; and it is a noteworthy fact that, while some of the 

 stones have decayed and fallen almost to powder, others have as 

 sharp edges, and exhibit the tool-marks as perfectly, as if but yesterday 

 brought from the quarry. Probably by exercising care in the selec- 

 tion of particular beds, and in laying the blocks in their natural 

 positions, this rock might still be made to furnish a very serviceable 

 building-stone. 



These beds of hard chalk have suffered less from denudation than 

 the superior and softer beds, and they rise into an almost continuous 

 * " On the Cretaceous G-roup in Norfolk," Proc. Geol. Assoc. 1862. 



