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 talcose, 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 as 
greenstone, trap and its varieties, and porphyry. ‘The trap dykes 
are numerous and exceedingly distinct; 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. 
rman ti GS ah 
