B. Thompson — Fresh-icater Shells in the Lincolnshire Oolite. 225 



may be three or four feet; but it thins out considerably towards the 

 adjacent road. 



3. The Lincolnshire Oolite here belongs to the so-called ** shelly 

 facies " ( Jiidd), that is, it consists almost wholly of small shells 

 or fragments of shells, mostly water-worn, or encrusted with 

 carbonate of lime, so that all trace of the finer ornamentation is 

 lost, together with concretions not obviously connected with the 

 shelly character. Gasteropods are more numerous than any other 

 form of fossil. 



[At some places in the neighbourhood the fossils of this ''shelly 

 facies " of the Lincolnshire Oolite are better preserved, and it was 

 from such, near to Weldon, that so many of the forms recently 

 described by Mr. Hudleston, in his Monograph on the Inferior Oolite 

 Gasteropoda, came.] 



The upper portion of the Oolite is soft and sandy-looking, and 

 can be picked out quite easily with a knife. The lower portion is 

 mostly harder, more compact, and even somewhat crystalline ; and 

 nodular or hummocky masses of this rise, in places, into the softer 

 zone above. The entire thickness exposed is as variable as the 

 clay and soil, etc., resting on it, but in the deepest part reaches 

 nine or ten feet. 



4. Here and there in the section are gullies, or "pipes," filled in 

 with Boulder-clay or gravel; they begin in the confused layers (2), 

 and mostly reach below the present working. 



The page section illustrating this paper has been produced from 

 a coloured diagram kindly made for me by Mr. Wallis last summer, 

 1894, and is a record of his personal observations. 



The section is really worked as a gravel-pit, and the finer oolitic 

 material, when screened, appears to be very good for garden paths 

 and such like purposes. It appears that the villagers have a right 

 to the gravel, whereas the soil above is private property, and so 

 things are in a peculiar position, and the privilege of digging gravel 

 is greatly curtailed. 



The recent shells that have been found at Brigstock all occurred 

 in the limestone, at four or five different places, some distance apart 

 horizontally, and at variable depths. The first and chief find was 

 at a spot, now enclosed and covered in by a hen-shed, some ten feet 

 below the surface of the ground, and seven feet below the upper 

 surface of the limestone. Here the shells occurred in a little patch 

 of clay, quite unconnected with the surface or the Boulder-clay, so 

 far as could be ascertained ; that is, they were not found in or near 

 to one of the "pipes" previously referred to. 



The shells that have been found are, or were at first, fairly 

 perfect, although extremely fragile, and bleached. They include 

 the following species : — 



Sttceinea putris. Helix nemoralis or arhustorum ? 



Cochlicopa lubrica. Pupa marginata. 



Helix pulcheUa. Pisidium pusillum. 



The shells were named by Mr. Lionel E. Adams, but one or two 

 were submitted to Mr. J. W. Taylor, of Leeds, for confirmation. 



DECADE IV. VOL. II. — NO. V. 15 



