Those Places Thursday - William Barlow Briggs' Family & Friends - 1880 Linn Co. Iowa?

This 10 x 8 photograph shows eight people posing outside a home.  It is a quite interesting piece and has puzzled me for some time.  This photograph was surely taken in Iowa although I had my doubts for some time.  If you look closely at the first photo you will see what appears to be mountains or at least large hills in the distance in the far left. I did not think that Iowa had mountains, but initial research shows that this area has what are called "pahas" or sand dunes which could explain this appearance in the photo as well as the woman with the broom. 

1880's Linn Co Iowa Group?

On the back the subjects are identified as:

William Briggs

Olive Jordan Briggs

Lillian Emma Briggs Taylor

Lou Henry Hoover

H. Maria Dobbins

Lillian Nudgett Horn

Jean Henry

Mrs. Henry

I have identified the male as William Barlow Briggs born 27 Sep 1837 in the state of Maine to Ezra and Phebe (Goddard) Briggs.  In 1866 he married Olive Jordan and their daughter Lillian was born in April of 1874.    The 1880 Maine, Linn County, Iowa shows Briggs living with his wife Olive and five year old daughter Lily. By 1900 the Briggs were living in Whittier City, Los Angeles, CA according to the US Census.  

William Barlow Briggs, Olive Jordan Briggs, Lillian Emma Briggs ca 1880-81

In this photo their daughter Lillian or Lily appears to be about five or six years old which would date this photograph about 1880 or 1881.  Additionally the women's clothing suggests an 1880's date.  Briggs appears to be handing his wife a document of some sort, perhaps a deed?  This type of photo was typically not seen until the later 1880's so hence my puzzlement.  I had no luck find any of the other women in the Linn County census so I am not sure of their connection to the Briggs'.  I have also been unable to identify the photographer as parts of the name have been torn off on both side of the picture.