PALiEONTOLOGICAL REPORT' OF GEOLOGICAL SURVEY. 523 



many assertions, that there does not exist a bed of true marine peat, 

 viz: peat formed entirely of fucoides and marine plants; and that he 

 has never seen a piece of coal with evident marks of marine origin. 



Have all our American coal-fields been formed in a continuous basin, 

 or is there any local one with an appreciable difference in the flora and 

 fauna of the shales ? 



Is there any trace of a permanent current of fresh water, of some 

 river having flowed either through the coal-fields during some time of 

 their formation, or in their vicinity ? 



Were the coal-fields the first land surface protruded like an island 

 from the sea, or were they true marshes, low shores of a continent, of 

 which the outlines had been already elevated above the ocean ? 



These are not the only questions that are to be answered. Beside 

 the mere practical advantage to be derived from the palaeontology of 

 coal, there is the nature of the vegetation, its relation to the atmos- 

 pherical phenomena of the epoch, its comparison with the flora of our 

 peat formations, and also with the coal flora of other continents, and 

 many other subjects, which open up to the geologist a most inter*- 

 esting field for the exercise of the mind. 



