MOUNDSOFOBSERVATION. 183 



This is a point which remains to be settled by the disclosures of the mattock and 

 spade, and by a close and extended observation of the dependences which exist, not 

 only between the hill-mounds themselves, but between them and the other monu- 

 ments of the same people. 



It may perhaps seem, from what has been adduced, that the classification of any 

 portion of the hill-mounds as places of observation, is not sufficiently well author- 

 ized. The positions however which many of them occupy, are such as would 

 most naturally be chosen for such purposes, though not necessarily for such only. 

 The apparent dependence which exists between some of them and the larger earth- 

 works would also seem to favor the idea that they were look-outs. But whether 

 signal-stations or otherwise, there can be no doubt that the ancient people selected 

 prominent and elevated positions upon which to build large fires, which were kept 

 burning for long periods, or renewed at frequent intervals. For wliat purposes 

 they were built, whether to communicate intelligence or to celebrate some religious 

 rite, it is not undertaken to say.* The traces of these fires are only observed 

 upon the brows of the hills : they appear to have been built generally upon heaps 

 of stones, which are broken up and sometimes partially vitrified. In all cases they 

 exhibit marks of intense and protracted heat. They are vulgarly supposed to 

 be the remains of "yi/rrtace.s," from the amount of scoriaceous material accompa- 

 nying them, which often covers a large area, and is several feet in tiiickness. 

 This popular error has led to some very extravagant conjectures as to the former 

 mineral wealth of the vicinity in which they occur ; an ei'ror which has been 

 perpetuated in various works on Amei-ican antiquities. 



The dependence which exists between certain mounds, and the defensive struc- 

 tures within or near which they are located, is too evident to admit of doubt. It 

 has already been made a subject of remark, (page 4.3,) and need only be referred 

 to here. In the case of the fortified hill. Plate VI, we find a large mound com- 

 manding the only avenue leading to it, and so placed that no approach could^be 

 made unobserved from its summit. Similar dependences, perhaps still more marked, 

 are perceived in other works, where mounds are placed on the approaches, or at 

 such points within or without the walls as are best adapted for observation. (See 

 Plate XI, Nos. 1 and 2.) 



* Wlien Lieut. Fremont penetrated into the fastnesses of Upper California, where his appearance created 

 great alarm among the Indians, he observed this primitive telegraphic sj'stem in operation. " Columns of 

 smoke rose over the country at scattered intervals, — signals by which the Indians, here as elsewhere, com- 

 municate to each other that enemies are in the country-. It is a signal of ancient and vcrv universal 

 application among barbarians." — Fremont's Second Expedition, p. 220. 



