THOMAS] LINES OF CONICAL MOUNDS. 537 



tion which can be offered in regard to the use of these low, connected 

 tumnli is that they were wigwam or house sites. The burnt chiy mixed 

 with charred grass at Aztahm indicates that, in some instances, they 

 were plastered, probably dome-shaped, or at least earth-walled, as were 

 many of the residences of Indians in former times. If this supposition, 

 which is strongly sn])ported by the data, be accepted, we must conclude 

 that in the northwest some change of custom had taken place, as here 

 we find but two mounds in a series, connected by embankments from iiO 

 to 1.50 yards in length. 



As will be noticed a little further on, there are a few conical (usually 

 burial) mounds which have uan-ow, ridge-like embankments extending 

 from them to a gi'eater or less distance. 



ROWS on LINKS OF CONICAL MOUNDS. 



We come now to another feature which appears to be confined almost 

 exclusively to the works of this district. This is found in the arrange- 

 ment of the ordinary conical mounds of the groups in rows, usually in a 

 single series. That this custom prevailed among the mound-builders of 

 the eastern portion of the district will be seen by referring to the plates 

 of Dr. Lapham's work and the figures of groups in the preceding field 

 report. In several instances this seems to be due to the topography of 

 the locality, such as the margin of a lake or bluff; but there are numer- 

 ous other cases where the level, open, and expanded area occupied per- 

 mitted any arrangement of the mounds and other structures agreeable 

 to the fancy of the builders. Hence we conclude that lines or rows of 

 mounds in siu'h localities furnish evidence of some peculiar custom of 

 the people who erected them. That they are attributable to the au- 

 thors of the efligy and elongate mounds is proved by several facts. One, 

 which seems to settle the question, is their intimate association with 

 these types. As illustrations of this statement the reader is referred to 

 Lapham's plate 48 and the plat of the Vilas group, Crawford county, 

 Wisconsin, in this volume. In both cases we see lines of works formed 

 of the three types, elongate, connected and separate mounds accom- 

 panied by effigies, and this on level, open areas, where there is ample 

 room for any desired arrangement. The intimate relation between 

 these forms and the propriety of attributing them to one people must, 

 therefore, be conceded. 



Another conclirsion which seems to be justified by a study of these 

 works and which has an imjiortant bearing upon their comparative 

 ages, is that there has been a gradual transition during the mound- 

 building age from one form to another. Api>arently this change has been 

 from the more conij)licated and massive forms to the* simple, conical 

 tumuli, ending with groups of this type, showing no decided tendency 

 to any specific arrangement, as in this last tyi)e we find evidences of 

 the most recent construction. The indications of sucli change were 

 noti<'ed by Dr. Lai)hain. who remarks: 



