The first six Hebrew lines read as follows:

Here lies
our dear father
an upright man pursuing righteousness [tzedakah] and lovingkindness [chesed]
the rabbi Mordechai son of Mr. Yechiel may his memory be a blessing
Michailover
Died on Purim [5]671 [1911] at the age of 67

The last Hebrew line is the standard Hebrew abbreviation for "May his soul be wrapped in the bundle [bonds] of life."

Between those initial and final lines, there is a wonderful acrostic poem, the initial letters of which form "Mordechai son of Yechiel."  Each line ends with the syllable "cha."

Why were you taken before your days were completed[?]
You did much [great things] for all who sought your aid
You trod the path of lovingkindness [chesed] all the days of your life
For your heart was full of mercy and pity [hearkening]
May you be repaid according to your deeds and your [deserved] recompense
When you come to seek refuge in the shade of your Creator
You will rest in peace on your resting place [bed, grave]
Will be remembered for the good to all who know your name
[for] the life and lovingkindness [chesed] that you did [wrought] in your earthly existence
Your years were 67 but your deeds were many
You are happy [worthy] that you ascended with your kind deeds
Those who fear God and all [others] turn to [await] your redemption

There's a strong sense that he died before his time, despite his relatively advanced years.

Shalom Leaf
NYC