250 



llEPORT OP THE SELECT COMMITTEE ON THE GEOLOGICAL SURVEY OP CANADA. [1855. 



If the filling in of the Lake is hurried on with as fest as possi- 

 ble, it can be comjileted before next winter, and then there 

 will be no danger to be apprehended for a long time to come. 



The manner in which the ice has affected the bridge is some- 

 what singular. As was predicted, there has been evidently a 

 raising of the entire field of ice since its formation. The effect 

 of this during the winter of 1853—4 was to draw out a few 

 piles, near the Indian shore, which had been imperfectly 

 driven, and to raise the whole, north of the truss bridge, some 

 sis or eight inches, except where it was held down by the 

 cribs, sunk every five hundred feet. This gave it rather an 

 undulating surface, and they were obliged to raise and block 

 up the stringers at these low points. It is proposed to prevent 

 this raising of the ice, by putting; flash-boards on the dam at 

 Crook's Rapids, at the lower end of Rice Lake, and raising it 

 some two or three feet before the ice takes. As more water 

 flows into the Lake it would be necessary to gradually take off' 

 the boards, and thus keep it at the same level. 



"When there is no snow on the ice, the heat of the sun in 

 the middle of the day expands it, and it moves slowly, carry- 

 ing the bridge with it. When night comes on and the tem- 

 perature falls, it contracts again, and cracks and splits in a sur- 

 prising manner. 



One of these cracks took place at a very acute angle across 

 the bridge, throwing one portion up stream about eighteen 

 inches, and the other down as much. 



The worst injury that the bridge has received was about the 

 1st of January of this year. The weather was particularly 

 trying, the days being warm and the nights very frosty ; and 

 this, it must be observed, is the only kind of weather in which 

 the bridge takes injury, — uniformly cold or warm weather not 

 affecting it. 



On this occasion there appeared to be an expansion of the 

 ice from the channel towards each shore, and the effect was 

 irresistible. The pile bridge north was thrown towards the 

 Indian shore ; but owing to the number of cribs in it, it 

 moved but little. The truss-bridge was pushed towards Tic 

 Island, so that the last span slid four feet upon the solid abut- 

 ment. South of Tic Island, the pile bridge was crowded over 

 toward the Cobourg shore, — so much, that at the place where 

 it parted, near the island, the stringers were drawn apart nearly 

 seven feet, so that they fell from the corbels. The piles were 

 leaned over, and where the thrust met the resistance of the 

 shore, it crushed up the solid 12"Xl8" stringers, and turned 

 them into splinters, and bent the iron rails double. This has all 

 been since repaired, and the trains are now crossing regularly. 



Prom inspection of the drawing. No. 6., accompanying, it 

 will be seen that nearly three-fourths of the length of the piles 

 are unsupported, and only one-fourth of them is in the solid 

 ground. When the thrast of the ice comes at the water-line, 

 it exerts a very powerful leverage, and it is not strange that 

 the bridge should yield. 



The dotted line in fig. 6 shows the outline of the embankment 

 which it is proposed to make. This, it will be seen, will support 

 the piles very much, and render it almost impossible that they 

 should be moved. In course of time, as the piles decay, it 

 will be found necessary to fill it up to the level of the track. 

 The embankment must then be protected from washing away 

 by a slope wall of loose stones and brush. Another very in- 

 genious method of protecting it has been proposed, which 

 would be less expensive than a slope wall. This is, to drive 

 piles some twenty feet from the bridge in rows parallel to it on 

 each side, cut them off below the depth to which the ice 

 forms, and chain to them a succession of spars forming a boom 



along the embankment on each side, and twenty feet from it. 

 It js believed that this would render the water calm enough 

 inside of it to prevent washing away the bank. 



The material on the south side of the Lake is admirably 

 adapted for filling, being a tough species of clay, or rather hard 

 pan, which, when thrown into the water, consolidates, and 

 packs around the piles, instead of washing away. A few hun- 

 dred feet of embankment was made of this material in the 

 summer of 1853, and has stood perfectly well ever since. 



The Rice Lake Bridge was designed and built under the 

 immediate superintendance of Ira Spalding, Esq., and reflects 

 great credit on that gentleman's skill and judgment as an 

 Engineer. The contractor was Mr. Zimmerman, whose well 

 known energy was severely taxed to supply so large an amount 

 of materials, and carry on the work to successful completion, 

 in spite of sickness and scarcity of workmen, in the compara- 

 tively short space of eighteen months. 



THOS. C. CLARKE. 



Port Hope, April, 2nd, 1855. 



Eeport of the Select Committee on the Geological Survey 

 of Canada.— Minutes of Evidence. 



In continuation* of the "Report of the Select Committee" 

 appointed by Parliament to inquire into the condition of the 

 Geological Survey of Canada, we proceed to furnish an ab- 

 stract of the Minutes of Evidence which accompanied the Re- 

 port. The importance which the Committee have very properly 

 attached to this great undertaking is thrown into relief, not so 

 much by the information elicited from witnesses respecting the 

 actual results of the Survey, as by the proofs of a marked and 

 highly complimentary attention, which the labors of Mr. Logan 

 and his staff have met with among European and American 

 Geologists and practical men. 



The first witness examined was Professor Hall, of Albany, 

 the author, among other valuable works, of the " Geology of 

 the Pirst District of the State of New York," and of those 

 magnificent volumes devoted to the Palseontology of the entire 

 State. Mr. Hall submitted in evidence that he had had 

 an opportunity of knowing much of the progress of the Ca- 

 nada Geological Survey from its commencement, and enter- 

 tained a very high opinion of the character and value of the 

 work which has been accomplished, as well as of its import- 

 ance to the Province, both in its Scientific and Economical 

 relations. 



In reply to the question, " What in your opinion would be 

 the best manner of placing the information and materials that 

 have been collected on the Canadian Survey before the public ?" 

 Mr. Hall considered it advisable to publish in one or 

 more volumes an account of the Geology of the Province, 

 which may be a revision and a condensation of the Reports of 

 Progress, with such illustrations by Geological Sections, Blaps, 

 Fossils, &c., as may be required for the proper elucidation of 

 the subject. Accompanying this volume should be a Geologi- 

 cal Map of the Province on a scale sufficiently large to repre- 

 sent all the Geological formations in their entii'e extent, each 

 formation being distinguished by a different color. This map 

 might also be accompanied with a small Pamphlet, describing 

 briefly the character and extent of the Pormations as repre- 

 sented on the map by different colors. It would be very de- 

 sirable to have copies of the complete work and the map so 

 distributed that it would be accessible for reference to every 



* See "Canadian Journal" Vol. HI., p. 234. 



