In and effort to help you out with your puzzel.The 1910 form has a column for relationship to the Head of Household and as long as the children belong to the Head of Household, those natural children will be listed in birth order after the wife regardless if she is or is not their natural born Mother.The woman in question Ida married second, probably had a previous marriage/husband and maybe grown or deceased/children by that husband so her answer may well be correct. I could not locate a column for (how many times a person had been married on either the 1910 or 1900 form.There is a column for how many years the person has been married to the Head of Household or spouse. It does not make it clear but apparently all the children listed belong to the head of household and at some point some of the children are his by her if they have been married long enough...if she is recorded as a Mother of children and states in the next column she has living children( two separate columns). It would seem most common that the Mother of that many children apparently died, as is most often the case in those days and the 2nd wife is listed in 1910. They are married for a year therefore her living children and Mother must be stated for children other than the Head of Household your GGrandfather.Men often married sisters or cousins of the first spouse.You might get lucky if they are from the Jones family. The border is quite common for the times as cousins, brothers or other relations lived with one another and they would always be listed last accordingly. That goes for orphans taken in also. I took Census in 2000 but the rules and regulations for Census have changed overtime.The person surnamed Jones may very well be related or it should be stated, cousin, step son, tennant, servant etc.I do not see a column on either Census asking how many TIMES a person was married. There is a column for the number of yearsthe person has been married and if that is a (1) then Ms Ida took over a brood of children and the previous Mother probably deceased. You May view a copy of these forms online for free.Most of the original script is pen and ink so spots of ink and errors in transcribing the originals happens more often than we of this digetal age expect.Hope this helps you out.The 1980 Census is online at www.familysearch.com and if you can find a family member there you might track them in that census.Do not neglect to use several different soundex, phonetic spellings as the material submmited on it until a few years ago was accepted without documentation from private parties and they are at liberty to spell the name however they wish.