INTRODUCTION. 



rpHE deep-sea corals described in these pages were collected in the 

 J_ years 1867, 1868, and 1869, during the expeditions made for the 

 exploration of the Gulf vStream by the United States Coast Survey, 

 B. Peirce, Superintendent, in the steamers Corwin and Bibb, Acting- 

 Master Robert Piatt, U. S. N., commanding. 



It will not be superfluous to preface their description by a condensed 

 statement of the successive steps taken by the Coast Survey in deep-sea 

 researches, and by a short review of our present knowledge of the con- 

 stitution of the bottom of the sea on the Atlantic coast of the United 

 States. The subject has been already treated in a paper published by 

 me in Petermann's Geogra'pliislie ^Ilttheilungen, but it may be well to 

 repeat it here for the benefit of English readers. 



The first step of the investigation may be said to have been taken 

 by the late Professor A. D. Bache, on his assuming the duties of super- 

 intendent of the United States Coast Survey in 1844, when he ordered 

 the preservation of the specimens brought up by the lead during the 

 progress of the hydrographical operations. The object was twofold, — 

 a practical one, to check the indications of the character of bottom laid 

 down on the charts by the hydrographei's ; and a scientific one, the for- 

 mation of a collection illustrating the character of the bottom and the 

 distribution of the materials constitutini*; it alono; our coast. 



The greater number of the specimens were obtained at first inside 

 of the hundred-fathom line, but the deeper waters of the Gulf Stream 

 soon began to add collections of still greater interest, if of less extent. 

 Simple contrivances were substituted for the usual tallow arming 

 the lead, so as to bring up the sand or mud in sufficient and uncon- 

 taminated quantities. Every specimen is placed in a small bottle, 

 labelled with the date, geographical position, and depth, and preserved 

 in cabinets arranged for the purpose in the Coast Survey Office in 

 Washington. 



The microscopical examination of the collection was begun by the 

 late Professor J. W. Bailey, of the Military Academy at West Point, 

 and after his death by myself, in the intervals of other duties. 



NO. IV. 1 



