50 TWELFTH REPORT. 



In the C. P. R. Salt Well, No. 11, at Windsor, are "dolomites" to a 

 depth of 300 feet, reported upon by an authority to whom it had not 

 then become necessary in the solving of Detroit river area problems, to 

 distinguish Avith precision between dolomites and limestones, for the 

 problems had not yet developed. Below this is 25 feet of "dark petroli- 

 ferous limestone." (Compare the 38 feet of problematical deposit in 

 the Salt Shaft with this.) Then follow 210 feet of dolomites, etc., above 

 55 feet of Sylvania. 



The question is: Is the Anderdon included in the one case? and: 

 Is this latter the problematical limestone? 



At the Sucker Creek test hole, there is 90 feet of gray limestone at 

 the top, which effervesces briskly. The location is about six miles from 

 the Amherstburg- quarries — where is the only recognized surface exten- 

 sion of, and the maximum depth of the Anderdon beds. Under the 90 feet 

 is 260 feet of brown dolomites, resting upon 30 feet of Sylvania. In the 

 proximity of 400 feet down from surface, or toward the bottom of the 

 dolomites which rest upon the saudrock, considerable effervescence is 

 observable. (With this compare the "petroliferous limestone" of the 

 Windsor salt well, and the problematical 38 feet of the Salt Shaft). 



The question again is: Is the Anderdon included in the one case? 

 and: Is this latter the problematical limestone of the Salt Shaft? 



The Amherstburg quarries have already been described in contrast 

 with Sibleys. and have been stated to be practically identical — except 

 for the later beds of thin-bedded Coniferous ( Dundee) at Sibleys, and 

 a maximum depth of Anderdon beds at the Amherstburg quarries. 



The Caldwell Grove well recorded in Brummel's "Natural Gas and 

 Petroleum in Ontario," 1892, has 252 feet of "limestone," (compare 

 as regards lack of jirecision in the use of terms, ''dolomite" in record of 

 surface deposits at Windsor salt well;) resting upon 60 feet of sand- 

 rock. 



The Dr. Green Shaft at Elliots Point has 25 feet of dolomite above 

 the Sylvania, with no Devonian overlying. This is at about the waist- 

 line, so to say, — the narrowest part — of the Cincinnati anticline, the 

 distance across from Elliots Point to the Huron River. 



I have attempted to suggest to you — without sufficient accurate 

 knowledge as yet being available for proof — that the contour of the 

 ''Anderdon beds" is continuous throughout the area traversed between 

 the extreme points, Elliots Point in Essex county, Ontario, and the 

 southeast corner of Wayne county, Michigan, in the near neighborhood 

 of which extreme points the Anderdon is acknowledged to be present. 



I have also attempted to suggest to you with some show of reason — 

 but again with only the same limited sources of inexact but suggestive 

 knowledge — that the supposed intercalated beds have, through at least 

 a gTeat part of the same area and distance, their own independent hori- 

 zon. 



Amherstburg, Ontario, Canada, April, 1910. 



