Notices of Memoirs — Sir W. Daicson on Fossil Algce. 503 



We have continued to investigate the great series of plant remains 

 so assiduously collected by Mr. A'Court Smith, and with this object 

 have visited Gurnet Bay, as well as receiving several packages of 

 fossils from thence. While lamenting that they are of so fragmentary 

 a nature, we cannot overlook their importance as almost the last 

 representatives of the great series of floras which maintained them- 

 selves in our area throughout the Eocene time. As an illustration of 

 their value, we may instance the fact that while anything like true 

 grasses seem to be wholly wanting in the previous floras, there are 

 many more or less definite indications of them in this. We have 

 reason to hope that renewed working in the still younger beds of 

 Hempstead may lead to further discoveries, for, besides the better 

 known plants described by Heer, pine-cones and a fine aro'ideous 

 fruit have been obtained from them. 



ITOTICES OIE 1 HUCZE^OIiaS. 



Papers read before the British Association for the Advancement of Science, 

 Birmingham, September, 1886, Section C (Geology). 



I. — On Canadian Examples of Supposed Fossil Illgm. By Sir 

 William Dawson, L.L.D., F.R.S. 



MARKINGS of various kinds on the surfaces of stratified rocks 

 have been loosely referred to Alga? or Fucoids under a great 

 variety of names ; and when recently the attempt was made in 

 Europe more critically to define and classify these objects, a great 

 divergence of opinion developed itself, of which the recent memoirs of 

 Nathorst, Williamson, Saporta, and Delgado may be taken as examples. 



The author, acting on a suggestion of Sir B. Owen, was enabled in 

 1862 and 1864, by the study of the footprints of the recent Limulus 

 polyphemus, to show that not merely the impressions known as Protich- 

 nites and Climactichnites, but also the supposed fucoids of the genera 

 Pusophycus, Arthrophycus, and Cruziana are really tracks of Crustacea, 

 and not improbably of Trilobites and Limuloids. 1 He had subsequently 

 applied similar explanations to a variety of other impressions found on 

 Ralseozoic rocks. 2 The object of the present paper was to illustrate by 

 a number of additional examples the same conclusions, and especially 

 to support the recent results of Eathorst and Williamson. 



Pusichnites, Arthrichnites, Chrossochorda, and Cruziana, with other 

 forms of so-called Bilobites, are closely allied to each other, and are 

 explicable by reference to the impressions left by the swimming and 

 walking feet of Limulus, and by the burrows of that animal. They 

 pass into Protichnites by such forms as the P. Davisii of Williamson, 

 and Saerichnites of Billings, and DiplicJinites of the author. They are 

 connected with the worm tracks of the genus Nereites by specimens of 

 Arthrichnites, in which the central furrow becomes obsolete, and by the 

 genus Gyrichnites of Whiteaves. 3 



1 "On Footprints of Limulus," Canad. Nat. 1862. "On the Fossils of the 

 Genus Ru&ophycus" Ibid. 1864. 



2 " On Footprints and Impressions of Aquatic Animals," Am. Journ. of Science. 



3 Trans. Koyal Society of Canada, 1883. 



