These data were obtained from the City of Arcata, Department of Environmental Services.  The following was provided by that department.

All shapefiles are in UTM Nad27, zone 10, units = meters

1.  Tidelands Mapping-Public Trust Lands(Former Tidelands) digitized from W.H. Pratt, U.S. Surveyor General, Swamp & Overflowed Lands, 1890-1891, UTM nad27 zone 10.

tidelnu27.shp............Limit of Swamp and Overflowed lands
tidelands_1890.pdf...Final GIS map:  1890 base map overlaid with current(1999)roads, parcels and waterbodies.
I'll include the Pratt survey map(for reference) .jpg when I find it. 

2.  Mad River Delta: Vegetation and Hydrography, J.S. Murray, 1854, U.S. Coast and Geodetic Survey map, 1870, UTM nad27 zone 10.

shorelineu27.shp................shoreline
h201870.shp.....................waterbodies
creeku27.shp....................creeks
veg1870.shp.....................vegetation in the year 1870
mad_river_delta_1870.jpg........scanned and reduced survey map(for reference)
mad_river_delta_1870_1997.jpg...Final GIS map: 1870 base map overlaid with current(1998)roads and current Mad river.
landuse00_u27.shp...............landuse during the year 2000
landuse41_u27.shp...............landuse during the year 1941

For both maps:

These maps were digitized from hard copies of the original survey at a scale that was not recorded.  The hard copy map was registered and digitized from a Calcomp 9100 digitizing board and processed with ArcInfo 7.1 workstation software.  Transformation errors were kept below .004(acceptable quality).  Hard copy map output processed in ArcView 3.1.

*Note*:  These maps were produced from scaled down copies of the original survey.  This was due to very limited access to large format scanners in this county during this time.  I know the county has recently accuired a large format scanner for these purposes.  If someone scans and digitizes the orginal survey map, my mapping will be obviously considered lower quality or obsolete.