I. Part of two letters from Mr. Edward Lhwyd, keeper of the Ashmolean repository in Oxford, to Mr. Samuel Dale of Braintree in Essex, concerning fossils

Abstract

The state of these bodies is quite different in your parts from what it is in Wales and Ireland . In those countries the shells are generally crystalline , but with you (and sometimes hereabouts) they are testaceous : which difference is doubtless to be attributed to the soil. and particularly to your chalk and flint, which not by chance of diluvian dissolution ) got into the north part of Ireland .