238 PHOCEEDINGS OF THE GEOLOGICAL SOCIETY. [-^W' 3, 



any opportunity of examining the stratigraphical relations of the 

 the bed, or of collecting its fossils ; and the following facts will 

 suffice to prove that such an identification is erroneous. 



1. The bed is always underlain by a great mass of the ordi- 

 nary hard white chalk, the exact thickness of which cannot be 

 exactly ascertained ; but it is certainly 40 feet, and probably much 

 more. 



2. The sponge-bed does not occur at its upper surface, though 

 at the outcrop of the true Hunstanton beds due west of Louth it is 

 well seen and presents all the usual characters. 



3. By far the most important fact in connexion with this subject, 

 however, is that, although I collected, with the greatest care, the 

 fossils of the Louth bed, not one specimen of Belemnites minimus 

 was found ; and out of a list of twenty fossils occurring in the bed, 

 only two, Terehratula bipUcata, Sow., and Terehratulina gracilis, 

 Schl., are common to it and the Hunstanton series ; and both of these 

 fossils have a very extended range in Lincolnshire. 



As this bed, unlike most of the other red beds in the chalk, can 

 be traced over a considerable area, I shall distinguish it in the re- 

 mainder of this paper by the name of the Louth Eed Chalk. 



By the side of the deep valley formed by the river Lud, is to be 

 seen a good section showing the hard white chalk with the red bed 

 in its midst. The whole appears to lie in irregular courses, with thin 

 clay partings ; and in the coloured portion of the section, these are of 

 the same pink tint as the chalk itself. This colour would be de- 

 scribed in hand-specimens as a very pale pink ; but viewed in the 

 mass and at a distance, the rock appears to be of a much more intense 

 colour, and is very conspicuous. The thickness of the bed is about 

 5 feet ; and it passes into the white chalk, both above and below, by 

 insensible gradations. The red rock has the earthy fracture and the 

 other physical characters of the adjoining white chalk, and displays 

 no signs of a nodular character, except towards the middle, where 

 there is a band of intensely hard nodules, breaking with a conchoidal 

 fracture, and exhibiting a perfectly white interior ; among these 

 occur abundantly the remains of Echini. The whole series of beds 

 is much broken up by a number of small faults ; and the same phe- 

 nomenon is exhibited in a greater or less degree in all the sections 

 where this bed is seen, 



Rather more than a mile south-west of this place, in a large 

 chalk-pit at HaUington, the same beds are seen ; and the red one can 

 be traced at intervals between these two sections. Although the 

 colour of the rock here is a little paler than at the last section, the 

 bed forms a very conspicuous object in the chalk-pit, which is on a 

 hillside, and it may be seen at the distance of several miles. The 

 section differs in no essential particulars from that on the banks of 

 the Lud ; and the red bed contains the same fossils. 



In the large chalk-pit near the Louth Union the bed is very 

 variable in colour, in some parts of a decided red. It is here 

 underlain by a grey sandy chalk containing nodules, and a branching 

 form like Sjpongia paradoocica, as also Pecten orbicularis, Sow., and 



