ijeology of England and Wales irc*^ 213 



ands along the coast of Massachusetts and Connecticut, ob- 

 viously belong to the same series of strata.* 



It is important in this place to remark, that the various 

 beds above the chalk, and, indeed, of almost all the secon- 

 dary strata below this, are identified, in different countries, 

 not so much by any resemblance in external, or chemical 

 characters, as hy the similarity of the organic remains found 

 In them- The discovery of this principle, (to be credited 

 to William Smith,) is one of the most fortunate achievments 

 of modern geology. For it would be wholly impossible, 

 in many cases, for the most experienced eye lo discriminate 

 between hand specimens from strata widely separated in 

 the earth. But here we have a clue, that rarely misleads; 

 and it shows us the importance and necessity of a study of 

 organised remains : — a subject, which is yet in its infancy, 

 even in Europe ; and still more so in this country. 



In the work under consideration, fifty pages are devoted 

 to a consideration of the strata above the chalk ; and many 

 interesting details are furnished. We have room to add 

 only a few remarks concerning the several members of the 

 series. 



The Upper Marine Formation occurs in three places in 

 England : viz. the Crag of Suffolk,! Bagshot Sand, and 

 a basin in the Isle of Wight. The first of these consists of 

 nearly horizontal beds of sand and gravel, and friable 

 masses of ferruginous sand, somewhat cemented together, 

 all of them enclosing shells : the second consists of sili- 

 ceous sand and sandstone without any cement, but contain- 

 ing shells ; and the third consists chiefly of a light green 

 marie, embracing immense quantities of shells. In all 

 these beds, the shells are of marine origin, and hence the 

 name of the formation. 



The Fresh Water Formations, so called because they 

 contain only fresh water shells, are divided into Upper and 

 Lower. These are separated by the interposition of the 

 Upper Marine Formation, which leads us to the certain 

 conclusion, that these different beds must have been de- 



* Since the above was written, we have been much interested in read- 

 ing, in the last number of this Journal, an Essay by Mr. Finch, on the Ter- 

 tiary Formations in America. The above suggestions are confirmed and 

 extended : and an attempt is made to refer us to the localities of seven dis- 

 tinct members of the formations above tl.-e chalk. We trust our geologists 

 will not disregard the important hints that Essay presents. 



t " Crag is a local name for gravel." — p. 1 1 . 



