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HARD WICKE'S SCIENCE- G OSSIK 



the Ontario basin about twenty miles east of 

 Toronto. The northern part of Lake Michigan 

 basin was drained into the Huron basin, as at 

 present ; whilst the southern basin of that lake 

 emptied by a now deeply drift-filled channel into the 

 south-western part of Huron. The buried fragments 

 of a great ancient valley and river, and its tributaries, 

 are connected with submerged channels in Lake 

 Huron and Lake Ontario, thus forming the course 

 of the ancient St. Lawrence (Laurentian) river, with 

 a great tributary from the Erie basin, and another 

 across the southern part of the State of Michigan. 

 This valley is of high antiquity, and was formed during 

 times of high continental elevation, culminating not 

 long before the Pleistocene period. The glaciation 

 of the region is nowhere parallel with the escarp- 

 ments, forming the sides of, or crossing the lakes or 

 less prominent features. During the Pleistocene 

 period, and especially at the close of the episode of 

 the upper Till, the continent was greatly depressed, 

 and extensive beaches and shore-lines were made, 

 which are now preserved at high elevations. With 

 the re-elevation of the continent these old water- 

 levels have been deformed, owing to their unequal 

 elevations. This deformation is sufficient to 

 account for the rocky barriers at the outlets of the 

 lakes. Some of the lakes have been formed, in part, 

 by drift obstructing the old valley. The origin of 

 the basins of the Great Lakes may be stated as the 

 valley (of erosion) of the ancient St. Lawrence River 

 and its tributaries, obstructed during, and particularly 

 at the close of the Pleistocene period, by terrestrial 

 movements, warping the earth's crust into barriers, 

 thus producing lake-basins, some of which had just 

 been formed in part by drift deposited in the ancient 

 valley. 



Professor Rucker's New " Divining Rod." — 

 We have heard a good deal concerning the divining 

 rod being used for finding underground supplies of 

 water. The trick is a very ancient one, and lost 

 nothing of its cleverness by being handed down for 

 , generations from father to son. The divining rod 

 could find out where copper, tin, lead, zinc, or other 

 metals lay buried below the surface of the earth, as 

 well as discover water. The only thing that led to 

 scepticism was that it professed to find too much. 

 But, after all, the divining rod, made of a twig of 

 hazel with a forked end, was perhaps the rude pre- 

 decessor of the scientific instrument which Professor 

 Rucker has just made known to the Royal Society ; 

 just as the rough Palaeolithic flint implement was the 

 antecedent of the modern surgeon's lancet and the 

 cavalry sword. Briefly, Professor Rucker's magneto- 

 meter is an adaptation of the well-known magnetic 

 compass. It indicates the occurrence of subterranean 

 strata lying beneath those which appear on the surface, 

 if they are magnetic or contain much iron, as basaltic 

 and many other igneous rocks do. Consequently, 



although this simple instrument cannot tell us if coal 

 occurs deep down beneath, it can pronounce where it 

 does not. In the important paper on " Coal in South- 

 Eastern England," read by Mr. William Whitaker 

 before the Society of Arts on April 23rd, Mr. Whita- 

 ker had occasion to refer to Professor Rucker's 

 recent discovery, and after the paper was read Pro- 

 fessor Rucker joined in the discussion. Professor 

 Rucker and Professor Thorpe (of Leeds) have for 

 some time past been noting the behaviour of the 

 magnetic needle in various parts of Great Britain, and 

 they found that it frequently misbehaves ; in other 

 words, it is deflected in certain places from what 

 would be regarded as its proper direction. The ex- 

 planation is that the deflection is due to great masses 

 of iron-bearing rocks, such as basalt, even when they 

 are buried up beneath chalk and tertiary strata. 

 Thus the new instrument has been the means of de- 

 monstrating hitherto unsuspected relations between 

 the magnetic properties and geological characters of 

 various districts. Professors Rucker and Thorpe have 

 in this way proved that there was magnetic attraction 

 along certain definite lines which run across England. 

 One is from the Lynn Wash to the line of the Mid- 

 land Railway between Hawes and Settle (in York- 

 shire), a distance of one hundred and fifty miles. 

 They further stated, with confidence, that a line from 

 somewhere near the South of the Thames, running 

 through the South Wales coal-field, was a line to 

 which the magnet was attracted, especially near 

 Reading. Professor Rucker is of opinion that the 

 needle is affected by the direct magnetic properties 

 of the underlying rocks, and this can only happen 

 where iron is present in considerable quantities. 

 How delicately the magnetic needle stands in relation 

 to the iron-bearing underground rocks beneath any 

 surface, is proved by the fact that considerable effects 

 might be produced upon it by rocks lying six or seven 

 thousand feet below. Where such iron-bearing rocks 

 are indicated to come up nearest the surface, coal 

 can hardly be expected to be found ; and, further, in 

 those localities where the underlying rocks come 

 nearest the surface, the downward pull on the 

 magnetic needle was found to be very great. 



NOTES AND QUERIES. 



Seasonable Notes. — April 1, swallow seen; 

 April 2, Viola tricolor in flower ; April 3, Glechoma 

 hederacea in flower — queen wasp seen ; April 6, hedge- 

 sparrow's nest with four eggs ; April 9, Stetiaria 

 holostea in flower; April 11, Plantago lanceolata in 

 flower, and crow-parsley ; April 12, sea-pink anneria 

 in flower ; April 14, Pedicularis sylvatica in flower — 

 larch in flower — blue-bell in flower ; April 16, Car- 

 damine pratctisis, dove's foot, cranebill, yellow pim- 

 pernell, and wild cherry in flower; April 17, Orchis 

 mascula in flower ; April 22, sycamore and Vicia 

 septum in flower — sand-martins seen ; April 23, 

 Veronica chanuedrys in flower ; April 24, Orobus 

 tubcrosus and wood-sanicle in flower — cuckoo heard ; 



