PEEFACE. 



One of the subjects comprehended in the recommendation of the 

 Select Committee appointed by the House of Assembly, on the 

 Geological Survey, in 1854, was the publication of figures and 

 descriptions illustrative of such new organic forms as might be 

 obtained in the progress of the investigation. In compliance with 

 this recommendation, it was determined that the publication should 

 be made in parts or decades, after the mode adopted by the 

 Geological Survey of the United Kingdom, each part to consist 

 of about -ten plates, with appropriate descriptive text, and to 

 comprehend one or more genera or groups of allied fossils, or the 

 description of several species, for the illustration of some special 

 point in geology. 



The first part or decade was confided for description, in 1855, to 

 Mr. J. W. Salter, one of the Palasontologists of the Geological 

 Survey of the United Kingdom. This comprehends different genera 

 and species from one locality. Of these several are new, while 

 others are more perfect forms of species already partially described ; 

 and the general object is to exhibit a commingling of forms here- 

 tofore supposed to belong to distinct epochs. The plates of this 

 decade are the work of Mr. W. Sowerby, from drawings by 

 Mr. R. C. Bone. The engravings are on steel ; nine of the plates 

 are finished, and it is expected the tenth will be completed in a 

 short time. 



The second decade was undertaken also in 1855, by Mr. James 

 Hall of Albany, so justly celebrated for his works on the Palaeon- 

 tology of New York. It will comprehend the description of a 

 large number of remarkable new forms of Grajptolithus and allied 

 genera from the Hudson River group. The drawings are by 



