The Barrettia Beds of Jamaica. 



501 



VII. COXCLUSION. 



In conclusion tlie writer wishes to express his thanks to Messrs. The 

 Yomah Oil Company (1920), Limited, for permission to publish the 

 original observations incorporated in this paper. To the officers 

 of the Geological Survey of India the most cordial thanks are 

 accorded. ^Vhen assistance has been given so whole-heartedly, it is 

 almost invidious to mention individuals, but in particular the writer 

 has profited by discussion with Dr. G. de P. Cotter and Mr. E. L. G. 

 Clegg, and by the help of Dr. J. Coggin Brown in the Survey's offices 

 at Calcutta. 



The Barrettia Beds of Jamaica. 



By C. T. Trechmaxx, D.Sc, F.G.S. 

 (PLATES XVin-XX). 



IXTRODUCTION. 



T^ARRETTIA, the most abnormal of the Rudistee, and among the 



strangest of all the mollusca, was first found in Jamaica by 



Lucas Barrett, F.G.S., in the vear 1861. The specimens were ably 



described by S. P. Woodward, F.G.S., in 1862.i The original 



1 " Some account of Barrettia, a new and remarkable shell from the Hippurite 

 Limestone of Jamaica " : The Geologist, London, 1862, pp. 372-7. 



