x¢evill POSTSCRIPT TO THE INTRODUCTION. 
or very nearly, where I had placed it—at the top of the Cambrian groups of England, and at 
the base of the May Hill Sandstone—and that my scheme of classification would, he believed, 
be more acceptable to American geologists than any other which had been published in this 
country. I may add, that the Professors Rogers both declared, during their successive visits to 
the Woodwardian Museum, that they saw in it an arrangement of the older Palzeozoic rocks of 
England which harmonized well with the grand natural series in North America. I know of 
no higher authorities: for the two Professors are excellent paleontologists; and have carried 
on their field-labours with very great and most happy skill, and with an amount of personal 
labour that is almost incredible. Such an accordance, on the other side of the Atlantic, as that 
above mentioned, was almost beyond hope: but in the development of the older Palzeozoic 
series of France we have a right to look for a near accordance with that of the corresponding 
rocks of England. On this subject I have no help, either from my own observations in the 
field, or from the collections of our Museum. I conclude, therefore, not with an affirmation 
but a question: Is not the older Paleozoic series of France in a good approximate accordance, 
both physically and paleontologically, with the older Palzozoic series of England, as given 
in this Introduction ? 
