138 MATTHEW ON CAMBEIAN 



in others on the Laurentian rocks. A good section may be seen at Hanford Brook, St. 

 Martin's, where it presents the following succession (ronghly estimated) : — 



Thickness 

 IN Feet. 

 1 — a- Coarse purplish red conglomerate resting on an amygdaloidal greenstone (toadstone) of 



the Coldbrook group 60 



6. Grey and purplish flags and sandstones with worm-casts, sea- weeds {l'alœocJiorda and Butho- 



IrepMs), and numerous spicules of sponges 70 



c. Purplish red sandstones, with greenish layers. Remains of sea-weeds {Phycoiddla), animal 



tracks (Pmmrmchinks and HchmiUlntes), worm-burrows ( AremcoH(cs), etc 2-10 



2 — a. Purplish red conglomerate, more friable than la 35 



h. Soft purplish red shales, with green glauconite grains, the upper part firmer and more 

 sandy, greenish grey layers interspersed especially towards the base. Platysolmitcs, Obolun, 



VolhorthcUu, etc 175 



c. Purplish sandy .shales, with a few bands of greenish shale. Worm-casls (.VcoWtcs) 3O0 



Measures concealed, probably of this series 320 



1,200 



In this series of one thousand or more feet of beds, the very oldest layers which are 

 fine enough to preserve organic markings, have trails and casts of marine worms, and 

 also contain seaweeds, one a Palœochorda or allied genus, the other a weed with a flat 

 frond similar to Buthotrephis. That these beds are marine is clearly shown by the 

 great numbers of spicules of hexactinellid sponges which they contain. 



About three hundred aud fifty feet above the base, where the measures are flaggy, 

 tracks of annelids are again abundant. Besides the smaller trails aud burrows, there are 

 frequent tracks of a marine animal, possibly a worm, similar to the markings on the 

 Fucoidal sandstone of Sweden, which, by Prof O. Terrell, have been referred to the genus 

 Psammichnites. A very similar track, with corresponding casts, occurs on the surfaces of 

 the purple streaked sandstones {Assise 3) of Band b in Division 1 of the St. John group, 

 and a similar trail occurs as high up as the lower Band of Division 2 of that group. 

 Above this point, such markings have not been found, though the kind of rock — flags 

 and slates — is favorable to their occurrence. The flags of the middle of Division 2 of 

 the St. John group seem to be the horizon of Crvziuna semiplicala (Salter) and C. similis 

 (Billings) ; but I have not found them here 



About one hundred feet or more above the horizon where Psammichnites appears, 

 separated from it by a conglomerate, indications of the Olenellus fauna show themselves. 

 These consist of Volborthella, (a chambered cell resembling an Orthoceras), the cystidean 

 genus Platysolenites, Pander, and a large Obolus, allied to Miclnvitzia (formerly Obolus ? or 

 Lingula ? ) vionilifera, Liurs, of the Eophyton sandstone of Sweden and the upper part of 

 the " Blue Clay " of Russia. Some of the layers in this part of the series abound in soft 

 green grains similar to the glauconite grains of the Cambrian rocks in Russia. The paste 

 enveloping them is red. 



A number of beds between this point and the top of the Basal series contain worm- 

 casts and burrows, and some have remains of small strap-like seaweeds. 



A sketch map showing the whole of the Basal series exposed on Hanford Brook is 

 given herewith, and the localities of the most important fossils indicated. By the section 

 given below it, the dip of the beds may be seen to be at a low angle in the lower divi- 

 sion. At the base of the upper division the dip increases considerably, and a change of 



