On the Inferior Oolite and Lias of Northamptonshire, fyc. 133 



This ' fish bed ' has been noticed by Mr. Morris in parts of 

 Lincolnshire and Northamptonshire on the Great Northern Rail- 

 way, and it is very probable that it will be detected in other 

 places where the Upper Lias occurs in situ, since it is rarely 

 wanting, in its course through Somersetshire and Gloucester- 

 shire, at the lower part of this deposit. In fact, this ' fish and 

 insect bed ' seems as persistent in the Upper Lias as the ' Insect 

 limestone ' is in the lower. 



The section at Bugbrook is as follows in descending order : 



ft. in. 



1. Rubbly white limestone in detached bits, in dark blue shale, with "I ^ Q 



numerous fragments of Ammonites / 



2. Thin-bedded limestone (' fish bed ') ; white externally, inside has ^ 



a green tinge with white specks ; it has a laminated fracture, [ Q 3 

 and splits readily when weathered ; it does not occur in nodules, f ' 

 but in a regular thin band in the clay J 



3. Thin, coarse, dark-coloured slaty stone, very rough, covered 



with spines, teeth and plates of Echinoderms, resting on the 

 marlstone. 



The thickness of the Upper Lias visible at this spot did not 

 exceed a few feet; it is succeeded by the Marlstone with the 

 usual fossils. I could not determine the total thickness of the 

 Upper Lias, as there was no section exposed, but there must be a 

 considerable mass of clay between the Inferior Oolite and the 

 small section at Bugbrook, though probably not half so thick as 

 the Upper Lias in Gloucestershire, which, according to Mr. Hull 

 of the Geological Survey, amounts at least to 200 feet in many 

 parts of the Cotteswolds. 



These strata, as well as those of the Inferior Oolite, are per- 

 fectly horizontal. When the Railway was in progress, the top 

 beds of the Lower Lias just below the Marlstone were exposed 

 at Kilsby, and were as usual very rich in fossils, similar for the 

 most part to those found in the equivalent strata at Campden, 

 and Hewlett's Hill near Cheltenham. 



The summit of Edge Hill in Warwickshire is capped by the 

 Marlstone, the Upper Lias having been denuded; but small 

 boulders of the ' fish bed/ containing scales of fish and ' Inoce- 

 ramus dubius* are of frequent occurrence in the vale below, 

 showing that it formerly occupied its normal position above the 

 Marlstone in that district. 



At Alderton, in Gloucestershire, the following strata were ex- 

 posed below the ' fish bed ' in April 1856, which seemed to be 

 richer in fossils than usual, and therefore I have noted them 

 here, which will enable the reader to compare them with those 

 at Bugbrook above mentioned. 



Brown and dark shales with many Ammonites, Inoceramus 



M M 



