Notes on the Fossils obtained from the Well-sinking at Swindon

Abstract

Kimerdge Clay . From 8 feet to 72 feet, Kimeridge Clay was passed through, but only a few fossils were collected: thus between 10 feet and 16 feet Rhynchonella inconstans , Shy., Ammonites cordatus , Sby., and Ostrea deltoidea , Sby., were noticed; at 45 feet Astarte and Thracia depressa , Sby., and from 45 feet to 52 feet Belemnites were met with. The earthy Limestone-bed with iron-shot grains, between 50 feet and 50½ feet, yielded:― Coral Rag The series of alternating beds, from 72 feet to 112 feet, probably represent the “Coral Rag,” but no determinable fossils were obtained from them, although there axe indications of shells and possibly Echinoderm spines. Oxford Clay . The beds from 119, feet to 685 feet are, no doubt, correctly referred to the Oxford Clay; but the occurrence in the lower parts of Ammonites Kvenigi , and of an Ammonite which cannot be distinguished from some forms of Am. calloviensis , would seem to indicato that these lower beds may be the equivalents of the Kellaways Rock. For convenience of comparison, the fossils have been divided inta groups corresponding to changes in the nature of the strata. Cornbrash . The fossils named in the list below were obtained from depths between 685 feet and 703 feet. Some of them were from the marly beds, but the exact position of the greater number is uncertain:― 3. Few fossils have been obtained from the Kimeridge Clay, but they include one Ammonite ( A. cordatus ), au Oxfordian form, which is known, however, from