The dolerite-chalk contact of Scawt Hill, Co. Antrim. The production of basic alkali-rocks by the assimilation of limestone by basaltic magma (With Plates XVII and XVIII.)

Abstract

In the following pages an account is given of the rock assemblages produced at the contact of a dolcrite intrusion with chalk. Owing to the intense localized assimilation of calcium carbonate by the dolerite magma, unusual rock types are produced. The products of the endogenous contact-zone are dealt with in detail. Those of the exogenous contact-zone have in part been described already, but some additional data are incorporated in this account.