142 VEEMES phylum hi 



vermiform structures known as " Hieroglyphics," which occur in the Flysch, 

 Carpathian Sandstone, and in the marine facies of the Cretaceous and Jurassic 

 formations. The trails known as Climactichnites Logan,^ from the Potsdam 

 sandstone (Cambrian) of New York and Wisconsin, are of uncertain origin, 

 but may be those of some large crustacean. Other peculiar markings have 

 been interpreted by B. B. Woodward {Proc. Malacol. Soc, London, 1906, vol, 

 vii.) as the feeding-tracks of Gastropods. 



^ These tracks, known as Olimactichnites, were first described by Logan {Oan. Nat. and Geol., 

 1860, vol. V.) and later recorded by Hall (N.Y. State Miis. 42nd Report, 1889) from Port Henry. 

 Essex connty, N.Y., and by Woodworth (N.Y. State Mus. Bull. 69, 1903) from the town of 

 Mooers, Clinton county, N.Y. In the latter locality they assume gigantic proportions, being 6 inches 

 wide and 15 or more feet long, terminating in an oval impression 16 inches long. 



Various explanations have been suggested for these tracks. Besides having been referred to 

 trilobites, burrowing crustaceans, plants, gastropods and annelids, they have been compared with 

 those of the horseshoe crab, first by Dawson and recently again by Hitchcock and Patten. Sir 

 William Dawson {Can. Nat. and Cfeol., 1862, vol. vii.), who studied Limulus on the seashore, 

 pointed out that when the animal creeps on quicksand, or on sand just covered with water, it uses 

 its ordinary wallcing legs and produces a track strikiugly like that described as Protichnites from 

 tile Potsdam saiidstone ; but in shallow water just covering the body, it uses its abdominal gill-plates 

 and produces a ladder-like track the exact counterpart of Climactichnites except that in the track of 

 Livmlus the lateral and median lines are furrows instead of ridges. Patten {Science, 1908, vol. viii. 

 p. 382) " described the inovements of a modern Limulus in advancing uj) a sandy beach with the tide, 

 and the action of the abdominal gill-plates making rhythmic ridges in the sand. He compared 

 these with the tracks of Climactichnites, which he ascril)ed to forms related to the eurypterids rather 

 than the trilobites. Tlie tracks showed a beginning in a hollow in the sand and where continued 

 on the specimen to the further end there became fainter, as if the animal rose fi'om the bottom. 

 This would correspond with the habit of the Limulus, which remains buried on recession of the tide 

 and upon its first return crawls and then swims away. Beside one track were seen two symmetric- 

 ally placed impressions attributed to the longer arms of a Eurypteroid form." 



In favour of this view is the fact that Struhops is a Cambrian Eurypterid that would appear 

 competent to produce such tracks ; contrariwise, however, Woodworth has suggested that the trail 

 was made by a mollusk, and that the sedentary impression is the end of the trail instead of its 

 beginning. Tlie direction of the obliquely transverse marks of Climactichnites is always toward 

 the oval impressions, and comparison with those of the Limulus tracks (Dawson, figs. 1-3, and also 

 fig. 157 in Cambridge Nat. Hist. vol. iv.) would indicate that the animal, if an Eurypterid, moved 

 toward the sedentary impression and not away from it. The most recent discussion of the nature 

 of these and other j)roblematical markings is to be found in a paper by Walcott (Smithson. Alisc. 

 Coll., 1912, vol. Ivii., no. 9), where it is suggested that the Climactichnites trails may have been 

 formed liy a large segmented Annelid like Pollingcria. Sjiecimens of the latter are known from 

 the Cambrian which have a length of 13 cm. and width of 7 cm. 



