36 SCLTDDER ON THE DEVONIAN 



for believing that the Dadoxylon sandstone and Cordaite shales may be equivalents of the 

 Hamilton group in New York and Ohio, ■which has afforded some fossil plants compara- 

 ble with those of the St. John beds, especially trunks of conifers of the genus Dadoxylon 

 {Araucaroxylon). The horizon of the fossil insects of St. John would thus be middle 

 devonian. 



In the finer shales of this series, the remains of plants are very perfectly preserved, 

 the most delicate leaves haAnng not only their outlines but also their nervature repre- 

 sented by films and lines of shining gi'aphite, resembling pencil drawings on a dark gray 

 ground. The insect wings are preserved in a similar manner. 



The discovery of the insect remains is wholly due to the late Pi'of C. F. Hartt, who, 

 with the aid of other gentlemen, members of the Natural History Society of New Bruns- 

 wick, removed by blasting large quantities of the richest fossiliferous beds and examined 

 them with great care. The extreme rarity of these remains renders it probable that 

 but for the large quantities of material examined by Professor Hartt, they would not 

 have been found ; while the extreme delicacy of the impressions would have prevented 

 them from being observed except .by a very careful collector scrutinizing every surface in 

 the search for leaflets of ferns, preserved in such a way as to be visible only under 

 the most fovorable light. These unusually perfect explorations should be taken into 

 the account in any comparisons made of the fossils of this locality with those of other 

 places. 



The following detailed section of the Little Eiver Group, at the Fern Ledges, Lancaster, 

 N. B., where the insects occur, is derived from Professor Hartt's paper in Bailey and 

 Matthew's report before alluded to, and is substantially the same as given in my Acadian 

 Geology. 



Section at the "Fern Ledges!' {Order ascending.) 



Heavy beds of gray sandstone and flags (Dadoxylon sandstone). Dadoxylon oitan- 



gondiamnn Daws., Calamites, etc. Thickness, by estimation, .300 feet. 



Under this head I have classed all the beds underlying the Plant-bed No. 1, which I am 

 disposed to regard as the lowest of the rich plant-bearing layers, and the base of the 

 Cordaite shales. These beds occupy the low ground lying between the ridge of the 

 Bloomslmry group and the shore. They are covered by drift, and show themselves only 

 in limited outcrops, and in the ledges on the shore. In the western part of the ledges 

 they are thrown forward on the beach by a fault, forming a prominent mass of rock, in 

 the summit of which a fine trunk of Dadoxylon is seen embedded in the sandstone. 

 Recent excavations made in these beds in quarrying stone for building purposes, in the 

 eastern part of the locality, where the roclvs are very much broken up by dislocations, 

 have exposed numerous badly preserved impressions of large trunks of this tree. 

 Plant-bed No. 1 Thickness, 1 foot. 



Black arenaceous shale, varying from a fissile sandstone to a semi- papyraceous shale, 

 very fine-grained and very fissile, charged most richly with beautifully preserved remains 

 of plants, among which are the following species : — 



Calamites transitionis Goeppert. (C. radlatus Br.) Occasional, in large, erect speci- 

 mens. — Asterojihyllites latlfoUa Daws. Extremely abundant, often showing ten or 

 twelve whorls of leaves, sometunes with many branches. — A. acicularis Daws. Also 



