LETTER OF TRANSMITTAL. 



Department of the Interior, 

 United States Geological Survey, 

 Division op Mesozoic Invertebrates, 



Washiiu/ton, D. C, October 15, 1891. 

 Sir: I herewith transmit the manuscript of a memoir on the Mesozoic 

 Echiuodermata of the United States by Dr. William B. Clark, which 

 you authorized him to prepare as a part of the work of the division of 

 the Survey in my charge. I recommend that it be i)ublished as a bulle- 

 tin of the Survey. 



Very respectfully, 



C. A. White, 



Oeologist in charge. 

 Hon. J. W. Powell, 



Director U. S. Geological Survey. 



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