AMERICAN GEOLOGY DECADE OF 1830-1839. 353 



two months and six days from the date of our actual commencement in the field. 

 Also several thousand specimens — some of rare beauty and interest— were collected, 

 arranged, and labeled. 



The. immediate result of this examination was to establish the fact 

 "that the district surveyed is one of the richest mineral regions, com- 

 pared to extent, jet known in the world." The area marked off as 

 including the productive lead region, as shown by his map. lay mainly 

 in Wisconsin, but comprised also a strip of about eight townships on 

 the Iowa side of the river and about ten townships in the northwest 

 corner of Illinois, the ore-bearing strata being limited to a heavy 

 bedded magnesian limestone which, on account of its characteristic 

 tendency to form perpendicular cliffs when subjected to weathering 

 and erosion, he called the Cliff limestone. This, he thought, from its 

 fossil remains, to be the equivalent of the Upper Silurian, and perhaps 

 a part of the Lower Silurian of Murchison. Though sparingly devel- 

 oped in the east, this, according to Owen, "swells in the Wisconsin 

 lead region into the most remarkable, most important, and most bulky 

 member of the group. It becomes, as it were, the Aaron's rod, swal- 

 lowing up all the rest," and attaining a thickness of upward of 500 

 feet." 



Owen's principal assistants were Dr. John Locke, who reported 

 mainly on the barometrical observations, with particular reference to 

 the measurement of altitudes and the making of geological sections, 

 and a Mr. E. Phillips, who reported on the timber, soil, and pro 

 ductiveness of the region. 



On April 18, 1838, Abraham Gesner, whose work in Nova Scotia 

 w T e have already referred to (p. 336), was appointed provincial geologist 

 of New Brunswick, a position he continued to hold until 1843, mak- 

 ing during this time live brief reports, comprising" 



Gesner's Work in & ° .... te 



New Brunswick, ill together but 440 pages. A partial geological map 

 was prepared, but never published. A considerable 

 portion of the reports was given up to a discussion of economic mat- 

 ters, particularly the coal beds, the value of which, as noted later, he 

 quite overestimated. The first four reports deal largely with that 

 portion of the province south of the Miramichi, Xashwaak, and St. 

 John's rivers. The fifth and last (1843) describes the country of the 

 upper St. John and that between the headwaters of the Tobique and 

 Ristigouche rivers. 



A gradual advance is to be noted, particularly where Gesner in bis 

 second report subdivided his graywacke, which he thought comparable 



"T<> .lames Hall's proposition to substitute the name Niagara tor Cliff, Owen 

 objected, claiming that the Niagara, as known in the east, represented only a part 

 of the formation he was describing, hi this last he was certainly right, more recent 

 work having shown that his Cliff limestone included also beds belonging to what is 

 now known as the Trenton period of the Lower Silurian. 

 NAT mis 1904 23 



