102 



MASSACHUSETTS AGRICULTUEE. 



100.00 



Remove the organic matter and water by decomposition, 

 and the residue "vvill be 59.36 parts, 40.28 parts of which, or 

 67.87 per cent, is pure bone phosphate of lime, which agrees 

 closely with the average composition of phosphatic rock, as it 

 is sold by the cargo to average 65 per cent. These are 

 chemical evidences and striking enough to convince ; but the 

 microscope reveals the truth fully and completely, for it is 

 easy to prepare samples of this rock which, on a slide, can 

 only be distinguished from recent bone by their color. There 

 can be no doubt then that these phosphates are strictly of 

 animal origin, and consist essentially of hone. 



By what means, chemical, physical or geological have they 

 been collected thus into these extensive and accessible depo- 

 sitions? How came the monsters of the sea to make this 

 their common burial-place for so many thousand years ? Es- 

 timating the area at fifty miles square, and the deposit to 

 average one thousand tons per acre, which is the lowest made 

 both for extent and quantity, and we have 1,600 million tons 

 of bone that remains intact after many thousand years, to say 

 nothing of the many millions that have been pulverized by 

 the action of the elements and entered into the composition 

 of the underlying marls. The imagination fails to compre- 

 hend an amount of living beings sufficient to bequeath a quan- 

 tity of bone so utterly incomprehensible. I have neither the 

 time nor the ability to discuss the geological features of this 

 question, and, with a single suggestion from Dr. Pratt, I 

 leave the matter to your imagination or investigation. 



There was a time — very recent in geological ages — when 

 the peninsula of Florida had no existence ; but the Gulf 

 Stream, after circling the western and northern shores of 

 what is now the Gulf of Mexico, swept its silent and majestic 



