680 



SCIENCE. 



[N. S. Vol. H. No; 47. 



and used for road making. At all tlie lo- 

 calities mentioned, except Williamsville, 

 the corals are in a siliceous pseudomorphous 

 condition; i. e., the original carbonate of 

 lime has been replaced by amorphous silica. 

 The surrounding limestone being so much 

 softer, on weathering it decomposes far 

 more rapidly than the included chert bands 

 and corals, and leaves them lying loose in 

 the soil or among the flakes of chert thrown 

 up by the farmer's plow. Collecting places 

 are usually easily discovered, since out- 

 crops of the Corniferous limestone are gen- 

 erally indicated by stone walls surrounding 

 the farms or bj^ stone piles scattered over 

 them. Four miles west of Port Colborne, 

 at one of Prof. Nicholson's localities, there 

 is a rock pile more than fifteen feet high, 

 every piece of which contains corals or 

 mollusca. At such places, one is inter- 

 ested often for days in turning over the 

 rocks and selecting the better specimens, 

 all of which can, if necessary, be further 

 developed with dilute hydrochloric acid. 



Towards the western portion of Ontario, 

 at Thedford, the next younger, or Hamil- 

 ton, formation is well exposed, and here 

 again corals are very abundant. This lo- 

 cality is probably the most famous for Mid- 

 dle Devonian fossils in North America, and 

 visiting collectors will find themselves plea- 

 santly surrounded with people who un- 

 derstand that a collector of fossils is neither 

 a curio collector nor insane. It is painful 

 to have the same question asked many 

 times each day: "Mister, what are you 

 looking for?" and after one has explained, 

 to observe in the listener no comprehension 

 of the first principles of geology, or, worse, 

 to be told: " I suppose you take them home 

 and gild them." But at Thedford one is 

 either left alone or assisted to find locali- 

 ties, or, better still, allowed to collect in the 

 cabinets of the minister, teacher, store- 

 keeper, tailor, or section boss. What a 

 splendid place Thedford is to the collector 



of fossils can be surmised on stating that 

 from one to five thousand specimens of the 

 brachiopod Spirifer mucronatug can be picked 

 up in a day. Thedford, formerly known as 

 AVidder, is made famous by the writings of 

 Billings, Hall and Whiteaves, and is visited 

 annually by collectors. Sometimes a col- 

 lege professor turns up with a car load of 

 students, including ladies. The local en- 

 thusiasm, however, has been developed by 

 the intelligent efforts of Eev. Hector Currie, 

 who, in a village of less than one thousand 

 inhabitants, is surrounded by four enthusi- 

 astic collectors. 



The Hamilton formation is again ob- 

 served on both sides of the southern penin- 

 sula of Michigan, near its northern ex- 

 tremity. Thunder Bay Island, situated 

 twelve miles east of Alpena, is almost one 

 mass of the coral-like Stromatopora, growing 

 in thin concentric laj'ers one upon another, 

 until single colonies assume a diameter of 

 from a few feet to the great width of three 

 yards. Upon these the sea of Lake Huron 

 has been pounding for ages, weathering 

 away the top of each wavy dome and sep- 

 arating the colony into innumerable, con- 

 centric, fractured layers. In a general way, 

 each mass resembles a transverse segment 

 of a huge tree trunk, and is often taken 

 for such by the local life-saving crew. In 

 the quarries north of Alpena, layers of 

 limestone nearly barren of fossils and less 

 than ten feet thick are seen to increase 

 rapidly to a thickness of nearly twenty 

 feet toward the coral reef, which is built up 

 hj Stroinato2)07-a', large Acermilaria:, numerous 

 compound branching corals, and here and 

 there a shell or the beautiful calyx of a 

 crinoid. Petoskey, on Lake Michigan, is 

 another well-known Devonian localitj^, and 

 is famous not only as a summer resort for 

 hay-fever sutt'erers, but for the ' Petoskey 

 stone ' as well. This stone is usually a 

 polished fragment of the coral Acermilaria 

 davickoni or of Favositeg alpenensis, and local 



