Hi Norman Franke.
My wife's grandmother was Emma Somers, probably descended from Matthias. We bought a copy of Rainer L. Hempel's book "New Voices on the Shores", published by the German Canadian Historical Society, Toronto 2000. ISBN 0-921415-08-7
Its a well researched book which gives family trees for 9 of the founding families of Moncton, the "Pennsylvania Dutch".

In SOMMERS, Matthias had 4 children by his first wife Christina Null (Married 23 Oct 1749 Philadelphia, died Phila. 1757).
*Anna Catharina, Bapt Nov 8 1753 Philadelphia
married Eliphalet Chappell
*Eva Magdalena, Bapt Feb 6 1753 Phila, died an infant.
*Sarah, born c 1755, Philadelphia area
Married Benjamin Allan
*Anna Christianna, born c 1757 Philadelphia
Married Nathaniel Fails
Married George Dobson
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Married Second wife in 1757 just after Christina Null died,
Maria Magdalena Aldmann (widow) Philadelphia, 4 more
*Elizabeth, born Phila 13 Feb 1759
Husband unknown
*Christina, born 1761/2 Phila Area,
Married Henry Jones
*Rachel, Born 31 Jan 1764 Barren Hill, Pa
Married Frederick Steiff
*Andrew (Andreas), born c 1765 probably in Barren Hill
Married Emily Beck (or Lewis, or Smith??)

Andrew had 2 sons, Matthias, Martin, and 8 daughters.

Hope this helps you John Coolen