GEOLOGY. 313 



fectly solid. At the top of the rod are two arms extending one from 

 each side. These arms being upon easily acting hinges, are capable 

 of being raised or lowered with very little power. A small branch 

 extends from the outside of each of them, which is for the purpose of 

 holding by means of rings a piece of wire by which the ball is swung 

 to the rod. A piece of rope is then attached by each end to the arms, 

 to which again is joined the sounding line. The ball is then lowered 

 into the water, and upon reaching the bottom the strain upon the line 

 ceases, and the arms fall down, allowing the ball to detach itself en- 

 tirely from the rod, which is then easily drawn in, the drilled por- 

 tion of which is discovered to be filled with a specimen of that which 

 it has come in contact with at the bottom. 



ORIGIN OF THE BITUMEN OF STRATIFIED ROCKS. 



The following is an abtract of a communication by Mr. Charles 

 Whittlesey, of Cleveland, Ohio, published in the Annals of Science. 



In the above caption I purposely abstain from using the word mineral 

 bitumen, as distinguished from that of plants, because most geologists 

 deny that there exists on the earth bituminous matter not derived 

 through either vegetable or animal life. In a tabular statement, I have 

 collected from all sources of information within my reach, the various 

 instances where bitumen flows from the rocks, or is embedded in their 

 composjtion in notable quantities. The exact geological position of 

 petroleum springs has not always been well determined by travellers. 

 It is not easy, therefore, to construct a table, such as I have under- 

 taken, in which we can place full confidence. 



The table embraces 68 cases, extending from the oldest sedimentary 

 rocks up through the column to the drift, and located in all portions 

 of the earth. 



The super-cretaceous rocks of South America, the cretaceous of 

 Syria, the oolite of France, and the lias of Europe furnish, out 



of sixty-eight 15 instances. 



The coal series and carboniferous rocks 8 



The Devonian rocks 13 



The Silurian 12 



The Metamorphic and Magnesian . 6 



I have classified the cases in the best/nanner the present state of 

 information in my possession admits ; but do not offer it as in every 

 respect correct. For convenience I have terminated the Devonian 

 system in Ohio and New York, at the base of the Black or Hamilton 

 Shales, and commenced the Silurian at the surface of the cliff or 

 Heldenberg limestones. In the present state of the discussion, it is 

 not easy to fix the true limit of those geological 1 divisions; and of 

 course if we use the terms Devonian and Silurian, an arbitrary line 

 of separation must be adopted for present purposes. I have placed 

 several instances of bituminous springs in the alluvium, drift, and ter- 

 tiary deposites ; but very much doubt whether in every case they do 

 not prdceed from subjacent rocks. 



