194 Geological Reports. 



diluvial deposits, and vast igneous formations, not only in the interior 

 but forming a barrier against the ocean surge, along a considerable 

 part of its immense sea coast, indented as it is by bays and estuaries 

 almost beyond example. Among the mineral formations of Maine, 

 are granite, gneiss, mica and lalcose, and other slates, including roof- 

 ing slate and alum slate ; also, soapstone, limestone, and marble — 

 sandstones and brecciated rocks of many varieties ; jasper, including 

 the beautiful ribbon variety ; lead, zinc, manganese and iron ;* 

 greenstone, trap and its varieties, and porphyry. The trap dykes 

 are numerous and exceedingly distinct 5 they cut through most of 

 the other rocks and produce upon them, most distinctly, those pecu- 

 liar effects, which to a demonstration prove their igneous origin. 

 Scientific geology is greatly indebted to this survey for some of the 

 most lucid and convincing facts on this head ; while the diluvial de- 

 posits, the boulders and ruins, the diluvial furrows in the rocks, the 

 sea shells now adhering to and inherent in rocks which once formed 

 the sea coast, although elevated twenty six feet above the sea board, 

 a salt spring at Lubec, and many other topics equally illustrate other 

 parts of scientific geology. Dr. Jackson is entirely master of his 

 subject, as well as of the kindred sciences of mineralogy and chem- 

 istry, and his report is remarkable for its lucid clearness and its at- 

 tractive style. 



In mentioning (however briefly and imperfectly) the labors of so 

 many able men, we are forcibly struck with the wide contrast be- 

 tween the present state of geological knowledge in our country and 

 that when in our early pursuits in this science, and its congeners — 

 even so late as the first conception of this Journal, (only twenty years 

 ago,) we could hardly find a glimmering taper to enable us to grope 

 our way through the thick darkness. Now if all is not light, cer- 

 tainly light is breaking in from all quarters, and the time is not distant 

 when we shall become acquainted with the geological resources of 

 the whole of this country, and even the entire continent ; and already 

 our native geologists have added much to the stores of geological 

 facts, and to the extension and elucidation of the science itself. 



* We have never heard of a case of natural magnetism equal to one named in 

 this report, where a bed of magnetic iron ore not only magnetized so powerfully 

 the iron instruments used to break it up as to adhere to them in large tufts of the 

 fragments of the iron ore, but, a crow bar suspended freely over the iron ore takes 

 the position in the magnetic meridian, and thus becomes a true but gigantic 

 needle. 



