126 Fossil Corals, — Lower Silurian Hods o/* Canada. 



Kg the branched variety. It is often seen on the surfaces of the strata of 

 limestone, partly imbedded in the rock, and resembling small broken twigs- 

 of trees. Often layers of shale are met with between the strata, packed full 

 of these short stems. They are from one-fourth to one-half of an inch in 

 diameter. The tubes are exceedingly slender and hair-like, seldom exceeding 

 one-fortieth of an inch in diameter. They are so small that it requires close- 

 examination of the surface of the coral to detect their presence. In the 

 branched variety they originate in the centre of the stem, and radiate out- 

 ward and upward. When such specimens are split open, this internal 

 arrangement of the tubes can be well seen. The other varietv is usuallv seen 

 in small hemispheric or button-shaped masses from half an inch to three 

 inches in diameter. Often they are globular, with a rounded concavity in 

 the bottom. Sometimes they are found with a projection below, gi^nng them; 

 the appearance of the stopper of a bottle, w^ith a w'ide mushroom-shaped 

 top. They also occur nearly fiat, or with the upper surface no more convex 

 than an ordinary watch glass.. The base of those flat specimens is wrinkled 

 concentricallv. These masses are formed of the same long slender tubes as 

 those Avhich constitute the branched variety. 



More than one hundred years ago, when geology was unkno^wn, a, 

 Swedish traveller, Peter Kalm, a Professor in the University of Abo, in 

 Swedish Finland, visited Canada, and in his narrative, gives the follov/ing 

 acconnt of the Fossils he savv^ in the Limestone at Fort St. Frederic, or 

 Crown Point, on Lake Champlain :— ^ 



" The moimtains on which Fort St. Frederic is built, as likewise those 

 on which the above kinds of stones are found, consisted generally of a deep, 

 black limestone, lying in lamellae as slates do, and it might be called a kind 

 of slates, which can be turned into quicklime by fire. This limestone is 

 quite black in the inside, and, when broken, appears to be of an exceeding 

 fine texture. There are some grains of a dark spar scattered in it, which,, 

 together with some other inequalities, form veins in it. The strata which 

 Ee uppermost in the mountains consist of a grey limestone, w^hich is, seem- 

 ingly no more than a variety of the preceding. The black limestone is. 

 constantly found filled with petrifactions of all kinds, and chiefly the following :: 



" Pedinites, or petrified Ostrece Pectines. These petrified shells were 

 more abundant than any others that have been found here, and sometimes; 

 whole strata are met with, consisting merely of a quantity of shells of this 

 PDrt, gix)wa. together. They are generally small, never exceding an inch and 

 a half in length. They are found in two different states of petrifaction ; onft 

 ghews always the impressions of the eleva,ted and hollow surfaces of the shells^ 

 without any vestige of the shells themselves. In the other appears the real 

 shell sticking in the stone, and by its light colour is easily distinguishable 

 from the stone. Both these kinds are plentiful in the stone ; however,, the: 

 impressions are more in number than the real shells. Some of the shells are 

 Tery elevated, especially in the middle, where they form as it were a hump ; 

 ©tilers again are depressed in the middle ; but in most of them the outward 

 furface k remarkably elevated. The furrows always run longitudinally, ojf> 

 fsom the top, diverging to the margiru 



