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Explanation of Plate VI. 
Fig. 1. Ogygites canadensis, (Chapman). An uncrushed specimen, in limestone, show- 
ing the course of the facial suture. Natural size. 
“ 2. Tctradiiim racemosum, Raymond. A weathered surface with several eoralla, 
one of them showing the style of branching common in Tetradia with this 
habit of growth. Natural size. 
“ 3. Telradium halysitoides, Raymond. Part of the weathered surface of a eorallum 
showing the “chain coral” form of growth. Twice natural size. 
“ 4. Telradium sp. ind. A form similar to T. cellulosum , Hall, but with only 4 
eorallites in a bundle. J natural size. 
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